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Immanuel Kant

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Immanuel KantFirst published Thu May 20, 2010

Immanuel Kant (1724–1804) is the central figure in modern philosophy.He synthesized early modern rationalism and empiricism, set the termsfor much of nineteenth and twentieth century philosophy, and continues toexercise a significant influence today in metaphysics, epistemology,ethics, political philosophy, aesthetics, and other fields. The fundamentalidea of Kant's “critical philosophy” — especially in his three Critiques:the Critique of Pure Reason (1781, 1787), the Critique of Practical Reason(1788), and the Critique of the Power of Judgment (1790) — is humanautonomy. He argues that the human understanding is the source of thegeneral laws of nature that structure all our experience; and that humanreason gives itself the moral law, which is our basis for belief in God,freedom, and immortality. Therefore, scientific knowledge, morality, andreligious belief are mutually consistent and secure because they all rest onthe same foundation of human autonomy, which is also the final end ofnature according to the teleological worldview of reflecting judgment thatKant introduces to unify the theoretical and practical parts of hisphilosophical system.

1. Life and works2. Kant's project in the Critique of Pure Reason

2.1 The crisis of the Enlightenment2.2 Kant's Copernican revolution in philosophy

3. Transcendental idealism3.1 The two-objects interpretation3.2 The two-aspects interpretation

4. The transcendental deduction4.1 Self-consciousness4.2 Objectivity and judgment

1

4.3 The law-giver of nature5. Morality and freedom

5.1 Theoretical and practical autonomy5.2 Freedom5.3 The fact of reason5.4 The categorical imperative

6. The highest good and practical postulates6.1 The highest good6.2 The postulates of pure practical reason

7. The unity of nature and freedom7.1 The great chasm7.2 The purposiveness of nature

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1. Life and works

Immanuel Kant was born April 22, 1724 in Königsberg, near thesoutheastern shore of the Baltic Sea. Today Königsberg has been renamedKaliningrad and is part of Russia. But during Kant's lifetime Königsbergwas the capitol of East Prussia, and its dominant language was German.Though geographically remote from the rest of Prussia and other Germancities, Königsberg was then a major commercial center, an importantmilitary port, and a relatively cosmopolitan university town.[1]

Kant was born into an artisan family of modest means. His father was amaster harness maker, and his mother was the daughter of a harnessmaker, though she was better educated than most women of her socialclass. Kant's family was never destitute, but his father's trade was in

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class. Kant's family was never destitute, but his father's trade was indecline during Kant's youth and his parents at times had to rely onextended family for financial support.

Kant's parents were Pietist and he attended a Pietist school, the CollegiumFridericianum, from ages eight through fifteen. Pietism was anevangelical Lutheran movement that emphasized conversion, reliance ondivine grace, the experience of religious emotions, and personal devotioninvolving regular Bible study, prayer, and introspection. Kant reactedstrongly against the forced soul-searching to which he was subjected atthe Collegium Fridericianum, in response to which he sought refuge inthe Latin classics, which were central to the school's curriculum. Later themature Kant's emphasis on reason and autonomy, rather than emotion anddependence on either authority or grace, may in part reflect his youthfulreaction against Pietism. But although the young Kant loathed his Pietistschooling, he had deep respect and admiration for his parents, especiallyhis mother, whose “genuine religiosity” he described as “not at allenthusiastic.” According to his biographer, Manfred Kuehn, Kant'sparents probably influenced him much less through their Pietism thanthrough their artisan values of “hard work, honesty, cleanliness, andindependence,” which they taught him by example.[2]

Kant attended college at the University of Königsberg, known as theAlbertina, where his early interest in classics was quickly superseded byphilosophy, which all first year students studied and which encompassedmathematics and physics as well as logic, metaphysics, ethics, and naturallaw. Kant's philosophy professors exposed him to the approach ofChristian Wolff (1679–1750), whose critical synthesis of the philosophyof G. W. Leibniz (1646–1716) was then very influential in Germanuniversities. But Kant was also exposed to a range of German and Britishcritics of Wolff, and there were strong doses of Aristotelianism andPietism represented in the philosophy faculty as well. Kant's favoriteteacher was Martin Knutzen (1713–1751), a Pietist who was heavily

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teacher was Martin Knutzen (1713–1751), a Pietist who was heavilyinfluenced by both Wolff and the English philosopher John Locke (1632–1704). Knutzen introduced Kant to the work of Isaac Newton (1642–1727), and his influence is visible in Kant's first published work,Thoughts on the True Estimation of Living Forces (1747), which was acritical attempt to mediate a dispute in natural philosophy betweenLeibnizians and Newtonians over the proper measurement of force.

After college Kant spent six years as a private tutor to young childrenoutside Königsberg. By this time both of his parents had died and Kant'sfinances were not yet secure enough for him to pursue an academiccareer. He finally returned to Königsberg in 1754 and began teaching atthe Albertina the following year. For the next four decades Kant taughtphilosophy there, until his retirement from teaching in 1796 at the age ofseventy-two.

Kant had a burst of publishing activity in the years after he returned fromworking as a private tutor. In 1754 and 1755 he published three scientificworks — one of which, Universal Natural History and Theory of theHeavens (1755), was a major book in which, among other things, hedeveloped what later became known as the nebular hypothesis about theformation of the solar system. Unfortunately, the printer went bankruptand the book had little immediate impact. To secure qualifications forteaching at the university, Kant also wrote two Latin dissertations: thefirst, entitled Concise Outline of Some Reflections on Fire (1755), earnedhim the Magister degree; and the second, New Elucidation of the FirstPrinciples of Metaphysical Cognition (1755), entitled him to teach as anunsalaried lecturer. The following year he published another Latin work,The Employment in Natural Philosophy of Metaphysics Combined withGeometry, of Which Sample I Contains the Physical Monadology (1756),in hopes of succeeding Knutzen as associate professor of logic andmetaphysics, though Kant failed to secure this position. Both the NewElucidation, which was Kant's first work concerned mainly with

Immanuel Kant


Elucidation, which was Kant's first work concerned mainly withmetaphysics, and the Physical Monadology further develop the positionon the interaction of finite substances that he first outlined in LivingForces. Both works depart from Leibniz-Wolffian views, though notradically. The New Elucidation in particular shows the influence ofChristian August Crusius (1715–1775), a German critic of Wolff.[3]

As an unsalaried lecturer at the Albertina Kant was paid directly by thestudents who attended his lectures, so he needed to teach an enormousamount and to attract many students in order to earn a living. Kant heldthis position from 1755 to 1770, during which period he would lecture anaverage of twenty hours per week on logic, metaphysics, and ethics, aswell as mathematics, physics, and physical geography. In his lecturesKant used textbooks by Wolffian authors such as Alexander GottliebBaumgarten (1714–1762) and Georg Friedrich Meier (1718–1777), but hefollowed them loosely and used them to structure his own reflections,which drew on a wide range of ideas of contemporary interest. Theseideas often stemmed from British sentimentalist philosophers such asDavid Hume (1711–1776) and Francis Hutcheson (1694–1747), some ofwhose texts were translated into German in the mid-1750's; and from theSwiss philosopher Jean-Jacques Rousseau (1712–1778), who published aflurry of works in the early 1760's. From early in his career Kant was apopular and successful lecturer. He also quickly developed a localreputation as a promising young intellectual and cut a dashing figure inKönigsberg society.

After several years of relative quiet, Kant unleashed another burst ofpublications in 1762–1764, including five philosophical works. The FalseSubtlety of the Four Syllogistic Figures (1762) rehearses criticisms ofAristotelian logic that were developed by other German philosophers. TheOnly Possible Argument in Support of a Demonstration of the Existenceof God (1762–3) is a major book in which Kant drew on his earlier workin Universal History and New Elucidation to develop an original

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in Universal History and New Elucidation to develop an originalargument for God's existence as a condition of the internal possibility ofall things, while criticizing other arguments for God's existence. The bookattracted several positive and some negative reviews. In 1762 Kant alsosubmitted an essay entitled Inquiry Concerning the Distinctness of thePrinciples of Natural Theology and Morality to a prize competition by thePrussian Royal Academy, though Kant's submission took second prize toMoses Mendelssohn's winning essay (and was published with it in 1764).Kant's Prize Essay, as it is known, departs more significantly fromLeibniz-Wolffian views than his earlier work and also contains his firstextended discussion of moral philosophy in print. The Prize Essay drawson British sources to criticize German rationalism in two respects: first,drawing on Newton, Kant distinguishes between the methods ofmathematics and philosophy; and second, drawing on Hutcheson, heclaims that “an unanalysable feeling of the good” supplies the materialcontent of our moral obligations, which cannot be demonstrated in apurely intellectual way from the formal principle of perfection alone(2:299).[4] These themes reappear in the Attempt to Introduce theConcept of Negative Magnitudes into Philosophy (1763), whose mainthesis, however, is that the real opposition of conflicting forces, as incausal relations, is not reducible to the logical relation of contradiction, asLeibnizians held. In Negative Magnitudes Kant also argues that themorality of an action is a function of the internal forces that motivate oneto act, rather than of the external (physical) actions or their consequences.Finally, Observations on the Feeling of the Beautiful and the Sublime(1764) deals mainly with alleged differences in the tastes of men andwomen and of people from different cultures. After it was published, Kantfilled his own interleaved copy of this book with (often unrelated)handwritten remarks, many of which reflect the deep influence ofRousseau on his thinking about moral philosophy in the mid-1760's.

These works helped to secure Kant a broader reputation in Germany, butfor the most part they were not strikingly original. Like other German

Immanuel Kant


for the most part they were not strikingly original. Like other Germanphilosophers at the time, Kant's early works are generally concerned withusing insights from British empiricist authors to reform or broaden theGerman rationalist tradition without radically undermining itsfoundations. While some of his early works tend to emphasize rationalistideas, others have a more empiricist emphasis. During this time Kant wasstriving to work out an independent position, but before the 1770's hisviews remained fluid.

In 1766 Kant published his first work concerned with the possibility ofmetaphysics, which later became a central topic of his mature philosophy.Dreams of a Spirit-Seer Elucidated by Dreams of Metaphysics, which hewrote soon after publishing a short Essay on Maladies of the Mind(1764), was occasioned by Kant's fascination with the Swedish visionaryEmanuel Swedenborg (1688–1772), who claimed to have insight into aspirit world that enabled him to make a series of apparently miraculouspredictions. In this curious work Kant satirically compares Swedenborg'sspirit-visions to the belief of rationalist metaphysicians in an immaterialsoul that survives death, and he concludes that philosophical knowledgeof either is impossible because human reason is limited to experience.The skeptical tone of Dreams is tempered, however, by Kant's suggestionthat “moral faith” nevertheless supports belief in an immaterial andimmortal soul, even if it is not possible to attain metaphysical knowledgein this domain (2:373).

In 1770, at the age of forty-six, Kant was appointed to the chair in logicand metaphysics at the Albertina, after teaching for fifteen years as anunsalaried lecturer and working since 1766 as a sublibrarian tosupplement his income. Kant was turned down for the same position in1758. But later, as his reputation grew, he declined chairs in philosophy atErlangen (1769) and Jena (1770) in hopes of obtaining one inKönigsberg. After Kant was finally promoted, he gradually extended hisrepertoire of lectures to include anthropology (Kant's was the first such

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repertoire of lectures to include anthropology (Kant's was the first suchcourse in Germany and became very popular), rational theology,pedagogy, natural right, and even mineralogy and military fortifications.In order to inaugurate his new position, Kant also wrote one more Latindissertation: Concerning the Form and Principles of the Sensible andIntelligible World (1770), which is known as the Inaugural Dissertation.

The Inaugural Dissertation departs more radically from both Wolffianrationalism and British sentimentalism than Kant's earlier work. Inspiredby Crusius and the Swiss natural philosopher Johann Heinrich Lambert(1728–1777), Kant distinguishes between two fundamental powers ofcognition, sensibility and understanding (intelligence), where the Leibniz-Wolffians regarded understanding (intellect) as the only fundamentalpower. Kant therefore rejects the rationalist view that sensibility is only aconfused species of intellectual cognition, and he replaces this with hisown view that sensibility is distinct from understanding and brings toperception its own subjective forms of space and time — a view thatdeveloped out of Kant's earlier criticism of Leibniz's relational view ofspace in Concerning the Ultimate Ground of the Differentiation ofDirections in Space (1768). Moreover, as the title of the InauguralDissertation indicates, Kant argues that sensibility and understanding aredirected at two different worlds: sensibility gives us access to the sensibleworld, while understanding enables us to grasp a distinct intelligibleworld. These two worlds are related in that what the understanding graspsin the intelligible world is the “paradigm” of “NOUMENALPERFECTION,” which is “a common measure for all other things in sofar as they are realities.” Considered theoretically, this intelligibleparadigm of perfection is God; considered practically, it is “MORALPERFECTION” (2:396). The Inaugural Dissertation thus develops a formof Platonism; and it rejects the view of British sentimentalists that moraljudgments are based on feelings of pleasure or pain, since Kant now holdsthat moral judgments are based on pure understanding alone.

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After 1770 Kant never surrendered the views that sensibility andunderstanding are distinct powers of cognition, that space and time aresubjective forms of human sensibility, and that moral judgments are basedon pure understanding (or reason) alone. But his embrace of Platonism inthe Inaugural Dissertation was short-lived. He soon denied that ourunderstanding is capable of insight into an intelligible world, whichcleared the path toward his mature position in the Critique of Pure Reason(1781), according to which the understanding (like sensibility) suppliesforms that structure our experience of the sensible world, to which humanknowledge is limited, while the intelligible (or noumenal) world is strictlyunknowable to us. Kant spent a decade working on the Critique of PureReason and published nothing else of significance between 1770 and1781. But its publication marked the beginning of another burst of activitythat produced Kant's most important and enduring works. Because earlyreviews of the Critique of Pure Reason were few and (in Kant's judgment)uncomprehending, he tried to clarify its main points in the much shorterProlegomena to Any Future Metaphysics That Will Be Able to ComeForward as a Science (1783). Among the major books that rapidlyfollowed are the Groundwork of the Metaphysics of Morals (1785),Kant's main work on the fundamental principle of morality; theMetaphysical Foundations of Natural Science (1786), his main work onnatural philosophy in what scholars call his critical period (1781–1798);the second and substantially revised edition of the Critique of PureReason (1787); the Critique of Practical Reason (1788), a fullerdiscussion of topics in moral philosophy that builds on (and in some waysrevises) the Groundwork; and the Critique of the Power of Judgment(1790), which deals with aesthetics and teleology. Kant also published anumber of important essays in this period, including Idea for a UniversalHistory With a Cosmopolitan Aim (1784) and Conjectural Beginning ofHuman History (1786), his main contributions to the philosophy ofhistory; An Answer to the Question: What is Enlightenment? (1784),which broaches some of the key ideas of his later political essays; and

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which broaches some of the key ideas of his later political essays; andWhat Does it Mean to Orient Oneself in Thinking? (1786), Kant'sintervention in the pantheism controversy that raged in Germanintellectual circles after F. H. Jacobi (1743–1819) accused the recentlydeceased G. E. Lessing (1729–1781) of Spinozism.

With these works Kant secured international fame and came to dominateGerman philosophy in the late 1780's. But in 1790 he announced that theCritique of the Power of Judgment brought his critical enterprise to anend (5:170). By then K. L. Reinhold (1758–1823), whose Letters on theKantian Philosophy (1786) popularized Kant's moral and religious ideas,had been installed (in 1787) in a chair devoted to Kantian philosophy atJena, which was more centrally located than Königsberg and rapidlydeveloping into the focal point of the next phase in German intellectualhistory. Reinhold soon began to criticize and move away from Kant'sviews. In 1794 his chair at Jena passed to J. G. Fichte, who had visited themaster in Königsberg and whose first book, Attempt at a Critique of AllRevelation (1792), was published anonymously and initially mistaken fora work by Kant himself. This catapulted Fichte to fame, but he too soonmoved away from Kant and developed an original position quite at oddswith Kant's, which Kant finally repudiated publicly in 1799 (12:370–371).Yet while German philosophy moved on to assess and respond to Kant'slegacy, Kant himself continued publishing important works in the 1790's.Among these are Religion Within the Boundaries of Mere Reason (1793),which drew a censure from the Prussian King when Kant published thebook after its second essay was rejected by the censor; The Conflict of theFaculties (1798), a collection of essays inspired by Kant's troubles withthe censor and dealing with the relationship between the philosophicaland theological faculties of the university; On the Common Saying: ThatMay be Correct in Theory, But it is of No Use in Practice (1793), TowardPerpetual Peace (1795), and the Doctrine of Right, the first part of theMetaphysics of Morals (1797), Kant's main works in political philosophy;the Doctrine of Virtue, the second part of the Metaphysics of Morals

Immanuel Kant


the Doctrine of Virtue, the second part of the Metaphysics of Morals(1797), a catalogue of duties that Kant had been planning for more thanthirty years; and Anthropology From a Pragmatic Point of View (1798),based on Kant's anthropology lectures. Several other compilations ofKant's lecture notes from other courses were published later, but thesewere not prepared by Kant himself.

Kant retired from teaching in 1796. For nearly two decades he had lived ahighly disciplined life focused primarily on completing his philosophicalsystem, which began to take definite shape in his mind only in middleage. After retiring he came to believe that there was a gap in this systemseparating the metaphysical foundations of natural science from physicsitself, and he set out to close this gap in a series of notes that postulate theexistence of an ether or caloric matter. These notes, known as the OpusPostumum, remained unfinished and unpublished in Kant's lifetime, andscholars disagree on their significance and relation to his earlier work. Itis clear, however, that these late notes show unmistakable signs of Kant'smental decline, which became tragically precipitous around 1800. Kantdied February 12, 1804, just short of his eightieth birthday.

2. Kant's project in the Critique of Pure Reason

The main topic of the Critique of Pure Reason is the possibility ofmetaphysics, understood in a specific way. Kant defines metaphysics interms of “the cognitions after which reason might strive independently ofall experience,” and his goal in the book is to reach a “decision about thepossibility or impossibility of a metaphysics in general, and thedetermination of its sources, as well as its extent and boundaries, all,however, from principles” (Axii. See also Bxiv; and 4:255–257). Thusmetaphysics for Kant concerns a priori knowledge, or knowledge whosejustification does not depend on experience; and he associates a prioriknowledge with reason. The project of the Critique is to examinewhether, how, and to what extent human reason is capable of a priori

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whether, how, and to what extent human reason is capable of a prioriknowledge.

2.1 The crisis of the Enlightenment

To understand the project of the Critique better, let us consider thehistorical and intellectual context in which it was written.[5] Kant wrotethe Critique toward the end of the Enlightenment, which was then in astate of crisis. Hindsight enables us to see that the 1780’s was atransitional decade in which the cultural balance shifted decisively awayfrom the Enlightenment toward Romanticism, but of course Kant did nothave the benefit of such hindsight.

The Enlightenment was a reaction to the rise and successes of modernscience in the sixteenth and seventeenth centuries. The spectacularachievement of Newton in particular engendered widespread confidenceand optimism about the power of human reason to control nature and toimprove human life. One effect of this new confidence in reason was thattraditional authorities were increasingly questioned. For why should weneed political or religious authorities to tell us how to live or what tobelieve, if each of us has the capacity to figure these things out forourselves? Kant expresses this Enlightenment commitment to thesovereignty of reason in the Critique:

Enlightenment is about thinking for oneself rather than letting othersthink for you, according to What is Enlightenment? (8:35). In this essay,Kant also expresses the Enlightenment faith in the inevitability of

Our age is the age of criticism, to which everything must submit.Religion through its holiness and legislation through its majestycommonly seek to exempt themselves from it. But in this way theyexcite a just suspicion against themselves, and cannot lay claim tothat unfeigned respect that reason grants only to that which hasbeen able to withstand its free and public examination (Axi).

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Kant also expresses the Enlightenment faith in the inevitability ofprogress. A few independent thinkers will gradually inspire a broadercultural movement, which ultimately will lead to greater freedom ofaction and governmental reform. A culture of enlightenment is “almostinevitable” if only there is “freedom to make public use of one's reason inall matters” (8:36).

The problem is that to some it seemed unclear whether progress would infact ensue if reason enjoyed full sovereignty over traditional authorities;or whether unaided reasoning would instead lead straight to materialism,fatalism, atheism, skepticism (Bxxxiv), or even libertinism andauthoritarianism (8:146). The Enlightenment commitment to thesovereignty of reason was tied to the expectation that it would not lead toany of these consequences but instead would support certain key beliefsthat tradition had always sanctioned. Crucially, these included belief inGod, the soul, freedom, and the compatibility of science with moralityand religion. Although a few intellectuals rejected some or all of thesebeliefs, the general spirit of the Enlightenment was not so radical. TheEnlightenment was about replacing traditional authorities with theauthority of individual human reason, but it was not about overturningtraditional moral and religious beliefs.

Yet the original inspiration for the Enlightenment was the new physics,which was mechanistic. If nature is entirely governed by mechanistic,causal laws, then it may seem that there is no room for freedom, a soul, oranything but matter in motion. This threatened the traditional view thatmorality requires freedom. We must be free in order to choose what isright over what is wrong, because otherwise we cannot be heldresponsible. It also threatened the traditional religious belief in a soul thatcan survive death or be resurrected in an afterlife. So modern science, thepride of the Enlightenment, the source of its optimism about the powersof human reason, threatened to undermine traditional moral and religiousbeliefs that free rational thought was expected to support. This was the

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beliefs that free rational thought was expected to support. This was themain intellectual crisis of the Enlightenment.

The Critique of Pure Reason is Kant's response to this crisis. Its maintopic is metaphysics because, for Kant, metaphysics is the domain ofreason – it is “the inventory of all we possess through pure reason,ordered systematically” (Axx) — and the authority of reason was inquestion. Kant's main goal is to show that a critique of reason by reasonitself, unaided and unrestrained by traditional authorities, establishes asecure and consistent basis for both Newtonian science and traditionalmorality and religion. In other words, free rational inquiry adequatelysupports all of these essential human interests and shows them to bemutually consistent. So reason deserves the sovereignty attributed to it bythe Enlightenment.

2.2 Kant's Copernican revolution in philosophy

To see how Kant attempts to achieve this goal in the Critique, it helps toreflect on his grounds for rejecting the Platonism of the InauguralDissertation. In a way the Inaugural Dissertation also tries to reconcileNewtonian science with traditional morality and religion, but its strategyis different from that of the Critique. According to the InauguralDissertation, Newtonian science is true of the sensible world, to whichsensibility gives us access; and the understanding grasps principles ofdivine and moral perfection in a distinct intelligible world, which areparadigms for measuring everything in the sensible world. So on thisview our knowledge of the intelligible world is a priori because it doesnot depend on sensibility, and this a priori knowledge furnishes principlesfor judging the sensible world because in some way the sensible worlditself conforms to or imitates the intelligible world.

Soon after writing the Inaugural Dissertation, however, Kant expresseddoubts about this view. As he explained in a February 21, 1772 letter to

Immanuel Kant


doubts about this view. As he explained in a February 21, 1772 letter tohis friend and former student, Marcus Herz:

Here Kant entertains doubts about how a priori knowledge of anintelligible world would be possible. The position of the InauguralDissertation is that the intelligible world is independent of the humanunderstanding and of the sensible world, both of which (in different ways)conform to the intelligible world. But, leaving aside questions about whatit means for the sensible world to conform to an intelligible world, how isit possible for the human understanding to conform to or grasp anintelligible world? If the intelligible world is independent of ourunderstanding, then it seems that we could grasp it only if we arepassively affected by it in some way. But for Kant sensibility is our

In my dissertation I was content to explain the nature ofintellectual representations in a merely negative way, namely, tostate that they were not modifications of the soul brought about bythe object. However, I silently passed over the further question ofhow a representation that refers to an object without being in anyway affected by it can be possible…. [B]y what means are these[intellectual representations] given to us, if not by the way inwhich they affect us? And if such intellectual representationsdepend on our inner activity, whence comes the agreement thatthey are supposed to have with objects — objects that arenevertheless not possibly produced thereby?…[A]s to how myunderstanding may form for itself concepts of things completely apriori, with which concepts the things must necessarily agree, andas to how my understanding may formulate real principlesconcerning the possibility of such concepts, with which principlesexperience must be in exact agreement and which nevertheless areindependent of experience — this question, of how the faculty ofunderstanding achieves this conformity with the things themselves,is still left in a state of obscurity. (10:130–131)

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passively affected by it in some way. But for Kant sensibility is ourpassive or receptive capacity to be affected by objects that areindependent of us (2:392, A51/B75). So the only way we could grasp anintelligible world that is independent of us is through sensibility, whichmeans that our knowledge of it could not be a priori. The pureunderstanding alone could at best enable us to form representations of anintelligible world. But since these intellectual representations wouldentirely “depend on our inner activity,” as Kant says to Herz, we have nogood reason to believe that they conform to an independent intelligibleworld. Such a priori intellectual representations could well be figments ofthe brain that do not correspond to anything independent of the humanmind. In any case, it is completely mysterious how there might come tobe a correspondence between purely intellectual representations and anindependent intelligible world.

Kant's strategy in the Critique is similar to that of the InauguralDissertation in that both works attempt to reconcile modern science withtraditional morality and religion by relegating them to distinct sensibleand intelligible worlds, respectively. But the Critique gives a far moremodest and yet revolutionary account of a priori knowledge. As Kant'sletter to Herz suggests, the main problem with his view in the InauguralDissertation is that it tries to explain the possibility of a priori knowledgeabout a world that is entirely independent of the human mind. This turnedout to be a dead end, and Kant never again maintained that we can have apriori knowledge about an intelligible world precisely because such aworld would be entirely independent of us. However, Kant's revolutionaryposition in the Critique is that we can have a priori knowledge about thegeneral structure of the sensible world because it is not entirelyindependent of the human mind. The sensible world, or the world ofappearances, is constructed by the human mind from a combination ofsensory matter that we receive passively and a priori forms that aresupplied by our cognitive faculties. We can have a priori knowledge onlyabout aspects of the sensible world that reflect the a priori forms supplied

Immanuel Kant


about aspects of the sensible world that reflect the a priori forms suppliedby our cognitive faculties. In Kant's words, “we can cognize of things apriori only what we ourselves have put into them” (Bxviii). So accordingto the Critique, a priori knowledge is possible only if and to the extentthat the sensible world itself depends on the way the human mindstructures its experience.

Kant characterizes this new constructivist view of experience in theCritique through an analogy with the revolution wrought by Copernicusin astronomy:

Up to now it has been assumed that all our cognition mustconform to the objects; but all attempts to find out somethingabout them a priori through concepts that would extend ourcognition have, on this presupposition, come to nothing. Hence letus once try whether we do not get farther with the problems ofmetaphysics by assuming that the objects must conform to ourcognition, which would agree better with the requested possibilityof an a priori cognition of them, which is to establish somethingabout objects before they are given to us. This would be just likethe first thoughts of Copernicus, who, when he did not make goodprogress in the explanation of the celestial motions if he assumedthat the entire celestial host revolves around the observer, tried tosee if he might not have greater success if he made the observerrevolve and left the stars at rest. Now in metaphysics we can try ina similar way regarding the intuition of objects. If intuition has toconform to the constitution of the objects, then I do not see howwe can know anything of them a priori; but if the object (as anobject of the senses) conforms to the constitution of our faculty ofintuition, then I can very well represent this possibility to myself.Yet because I cannot stop with these intuitions, if they are tobecome cognitions, but must refer them as representations tosomething as their object and determine this object through them, I

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As this passage suggests, what Kant has changed in the Critique isprimarily his view about the role and powers of the understanding, sincehe already held in the Inaugural Dissertation that sensibility contributesthe forms of space and time — which he calls pure (or a priori) intuitions(2:397) — to our cognition of the sensible world. But the Critique claimsthat pure understanding too, rather than giving us insight into anintelligible world, is limited to providing forms — which he calls pure ora priori concepts — that structure our cognition of the sensible world. Sonow both sensibility and understanding work together to constructcognition of the sensible world, which therefore conforms to the a prioriforms that are supplied by our cognitive faculties: the a priori intuitions ofsensibility and the a priori concepts of the understanding. This account isanalogous to the geocentric revolution of Copernicus in astronomybecause both require contributions from the observer to be factored intoexplanations of phenomena, although neither reduces phenomena to thecontributions of observers alone.[6] The way celestial phenomena appearto us on earth, according to Copernicus, is affected by both the motions ofcelestial bodies and the motion of the earth, which is not a stationary body

something as their object and determine this object through them, Ican assume either that the concepts through which I bring aboutthis determination also conform to the objects, and then I am onceagain in the same difficulty about how I could know anythingabout them a priori, or else I assume that the objects, or what isthe same thing, the experience in which alone they can becognized (as given objects) conforms to those concepts, in whichcase I immediately see an easier way out of the difficulty, sinceexperience itself is a kind of cognition requiring theunderstanding, whose rule I have to presuppose in myself beforeany object is given to me, hence a priori, which rule is expressedin concepts a priori, to which all objects of experience musttherefore necessarily conform, and with which they must agree.(Bxvi-xviii)

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celestial bodies and the motion of the earth, which is not a stationary bodyaround which everything else revolves. For Kant, analogously, thephenomena of human experience depend on both the sensory data that wereceive passively through sensibility and the way our mind activelyprocesses this data according to its own a priori rules. These rules supplythe general framework in which the sensible world and all the objects (orphenomena) in it appear to us. So the sensible world and its phenomenaare not entirely independent of the human mind, which contributes itsbasic structure.

How does Kant's Copernican revolution in philosophy improve on thestrategy of the Inaugural Dissertation for reconciling modern science withtraditional morality and religion? First, it gives Kant a new and ingeniousway of placing modern science on an a priori foundation. He is now in aposition to argue that we can have a priori knowledge about the basiclaws of modern science because those laws reflect the human mind'scontribution to structuring our experience. In other words, the sensibleworld necessarily conforms to certain fundamental laws — such as thatevery event has a cause — because the human mind constructs itaccording to those laws. Moreover, we can identify those laws byreflecting on the conditions of possible experience, which reveals that itwould be impossible for us to experience a world in which, for example,any given event fails to have a cause. From this Kant concludes thatmetaphysics is indeed possible in the sense that we can have a prioriknowledge that the entire sensible world — not just our actual experience,but any possible human experience — necessarily conforms to certainlaws. Kant calls this immanent metaphysics or the metaphysics ofexperience, because it deals with the essential principles that areimmanent to human experience.

But, second, if “we can cognize of things a priori only what we ourselveshave put into them,” then we cannot have a priori knowledge about thingswhose existence and nature are entirely independent of the human mind,

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whose existence and nature are entirely independent of the human mind,which Kant calls things in themselves (Bxviii). In his words: “[F]rom thisdeduction of our faculty of cognizing a priori [...] there emerges a verystrange result [...], namely that with this faculty we can never get beyondthe boundaries of possible experience, [...and] that such cognition reachesappearances only, leaving the thing in itself as something actual for itselfbut uncognized by us” (Bxix-xx). That is, Kant's constructivist foundationfor scientific knowledge restricts science to the realm of appearances andimplies that a priori knowledge of things in themselves that transcendpossible human experience — or transcendent metaphysics — isimpossible. In the Critique Kant thus rejects the insight into an intelligibleworld that he defended in the Inaugural Dissertation, and he now claimsthat rejecting knowledge about things in themselves is necessary forreconciling science with traditional morality and religion. This is becausehe claims that belief in God, freedom, and immortality have a strictlymoral basis, and yet adopting these beliefs on moral grounds would beunjustified if we could know that they were false. “Thus,” Kant says, “Ihad to deny knowledge in order to make room for faith” (Bxxx).Restricting knowledge to appearances and relegating God and the soul toan unknowable realm of things in themselves guarantees that it isimpossible to disprove claims about God and the freedom or immortalityof the soul, which moral arguments may therefore justify us in believing.Moreover, the determinism of modern science no longer threatens thefreedom required by traditional morality, because science and thereforedeterminism apply only to appearances, and there is room for freedom inthe realm of things in themselves, where the self or soul is located. Wecannot know (theoretically) that we are free, because we cannot knowanything about things in themselves. But there are especially strong moralgrounds for the belief in human freedom, which acts as “the keystone”supporting other morally grounded beliefs (5:3–4). In this way, Kantreplaces transcendent metaphysics with a new practical science that hecalls the metaphysics of morals. It thus turns out that two kinds of

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calls the metaphysics of morals. It thus turns out that two kinds ofmetaphysics are possible: the metaphysics of experience (or nature) andthe metaphysics of morals, both of which depend on Kant's Copernicanrevolution in philosophy.

3. Transcendental idealism

Perhaps the central and most controversial thesis of the Critique of PureReason is that human beings experience only appearances, not things inthemselves; and that space and time are only subjective forms of humanintuition that would not subsist in themselves if one were to abstract fromall subjective conditions of human intuition. Kant calls this thesistranscendental idealism.[7] One of his best summaries of it is arguably thefollowing:

We have therefore wanted to say that all our intuition is nothingbut the representation of appearance; that the things that we intuitare not in themselves what we intuit them to be, nor are theirrelations so constituted in themselves as they appear to us; and thatif we remove our own subject or even only the subjectiveconstitution of the senses in general, then all constitution, allrelations of objects in space and time, indeed space and timethemselves would disappear, and as appearances they cannot existin themselves, but only in us. What may be the case with objectsin themselves and abstracted from all this receptivity of oursensibility remains entirely unknown to us. We are acquaintedwith nothing except our way of perceiving them, which is peculiarto us, and which therefore does not necessarily pertain to everybeing, though to be sure it pertains to every human being. We areconcerned solely with this. Space and time are its pure forms,sensation in general its matter. We can cognize only the former apriori, i.e., prior to all actual perception, and they are thereforecalled pure intuition; the latter, however, is that in our cognition

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Kant introduces transcendental idealism in the part of the Critique calledthe Transcendental Aesthetic, and scholars generally agree that for Kanttranscendental idealism encompasses at least the following claims:

In some sense, human beings experience only appearances, notthings in themselves.Space and time are not things in themselves, or determinations ofthings in themselves that would remain if one abstracted from allsubjective conditions of human intuition. [Kant labels this conclusiona) at A26/B42 and again at A32–33/B49. It is at least a crucial partof what he means by calling space and time transcendentally ideal(A28/B44, A35–36/B52)].Space and time are nothing other than the subjective forms of humansensible intuition. [Kant labels this conclusion b) at A26/B42 andagain at A33/B49–50].Space and time are empirically real, which means that “everythingthat can come before us externally as an object” is in both space andtime, and that our internal intuitions of ourselves are in time(A28/B44, A34–35/B51–51).

But scholars disagree widely on how to interpret these claims, and there isno such thing as the standard interpretation of Kant's transcendentalidealism. Two general types of interpretation have been especiallyinfluential, however. This section provides an overview of these twointerpretations, although it should be emphasized that much importantscholarship on transcendental idealism does not fall neatly into either ofthese two camps.

called pure intuition; the latter, however, is that in our cognitionthat is responsible for its being called a posteriori cognition, i.e.,empirical intuition. The former adheres to our sensibilityabsolutely necessarily, whatever sort of sensations we may have;the latter can be very different. (A42/B59–60)[8]

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these two camps.

3.1 The two-objects interpretation

The two-objects reading is the traditional interpretation of Kant'stranscendental idealism. It goes back to the earliest review of the Critique— the so-called Göttingen review by Christian Garve (1742–1798) and J.G. Feder (1740–1821)[9] — and it was the dominant way of interpretingKant's transcendental idealism during his own lifetime. It has been a liveinterpretive option since then and remains so today, although it no longerenjoys the dominance that it once did.[10]

According to the two-objects interpretation, transcendental idealism isessentially a metaphysical thesis that distinguishes between two classes ofobjects: appearances and things in themselves. Another name for thisview is the two-worlds interpretation, since it can also be expressed bysaying that transcendental idealism essentially distinguishes between aworld of appearances and another world of things in themselves.

Things in themselves, on this interpretation, are absolutely real in thesense that they would exist and have whatever properties they have evenif no human beings were around to perceive them. Appearances, on theother hand, are not absolutely real in that sense, because their existenceand properties depend on human perceivers. Moreover, wheneverappearances do exist, in some sense they exist in the mind of humanperceivers. So appearances are mental entities or mental representations.This, coupled with the claim that we experience only appearances, makestranscendental idealism a form of phenomenalism on this interpretation,because it reduces the objects of experience to mental representations. Allof our experiences – all of our perceptions of objects and events in space,even those objects and events themselves, and all non-spatial but stilltemporal thoughts and feelings – fall into the class of appearances thatexist in the mind of human perceivers. These appearances cut us off

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exist in the mind of human perceivers. These appearances cut us offentirely from the reality of things in themselves, which are non-spatialand non-temporal. Yet Kant's theory, on this interpretation, neverthelessrequires that things in themselves exist, because they must transmit to usthe sensory data from which we construct appearances. In principle wecannot know how things in themselves affect our senses, because ourexperience and knowledge is limited to the world of appearancesconstructed by and in the mind. Things in themselves are therefore a sortof theoretical posit, whose existence and role are required by the theorybut are not directly verifiable.

The main problems with the two-objects interpretation are philosophical.Most readers of Kant who have interpreted his transcendental idealism inthis way have been — often very — critical of it, for reasons such as thefollowing:

First, at best Kant is walking a fine line in claiming on the one hand thatwe can have no knowledge about things in themselves, but on the otherhand that we know that things in themselves exist, that they affect oursenses, and that they are non-spatial and non-temporal. At worst histheory depends on contradictory claims about what we can and cannotknow about things in themselves. This objection was influentiallyarticulated by Jacobi, when he complained that “without thatpresupposition [of things in themselves] I could not enter into the system,but with it I could not stay within it” (Jacobi 1787, 336).

Second, even if that problem is surmounted, it has seemed to many thatKant's theory, interpreted in this way, implies a radical form of skepticismthat traps each of us within the contents of our own mind and cuts us offfrom reality. Some versions of this objection proceed from premises thatKant rejects. One version maintains that things in themselves are realwhile appearances are not, and hence that on Kant's view we cannot haveexperience or knowledge of reality. But Kant denies that appearances are

Immanuel Kant


experience or knowledge of reality. But Kant denies that appearances areunreal: they are just as real as things in themselves but are in a differentmetaphysical class. Another version claims that truth always involves acorrespondence between mental representations and things in themselves,from which it would follow that on Kant's view it is impossible for us tohave true beliefs about the world. But just as Kant denies that things inthemselves are the only (or privileged) reality, he also denies thatcorrespondence with things in themselves is the only kind of truth.Empirical judgments are true just in case they correspond with theirempirical objects in accordance with the a priori principles that structureall possible human experience. But the fact that Kant can appeal in thisway to an objective criterion of empirical truth that is internal to ourexperience has not been enough to convince some critics that Kant isinnocent of an unacceptable form of skepticism, mainly because of hisinsistence on our irreparable ignorance about things in themselves.

Third and finally, Kant's denial that things in themselves are spatial ortemporal has struck many of his readers as incoherent. The role of thingsin themselves, on the two-object interpretation, is to affect our senses andthereby to provide the sensory data from which our cognitive facultiesconstruct appearances within the framework of our a priori intuitions ofspace and time and a priori concepts such as causality. But if there is nospace, time, change, or causation in the realm of things in themselves,then how can things in themselves affect us? Transcendental affectionseems to involve a causal relation between things in themselves and oursensibility. If this is simply the way we unavoidably think abouttranscendental affection, because we can give positive content to thisthought only by employing the concept of a cause, while it is neverthelessstrictly false that things in themselves affect us causally, then it seems notonly that we are ignorant of how things in themselves really affect us. Itseems, rather, to be incoherent that things in themselves could affect us atall if they are not in space or time.

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3.2 The two-aspects interpretation

The two-aspects reading attempts to interpret Kant's transcendentalidealism in a way that enables it to be defended against at least some ofthese objections. On this view, transcendental idealism does notdistinguish between two classes of objects but rather between twodifferent aspects of one and the same class of objects. For this reason it isalso called the one-world interpretation, since it holds that there is onlyone world in Kant's ontology, and that at least some objects in that worldhave two different aspects: one aspect that appears to us, and anotheraspect that does not appear to us. That is, appearances are aspects of thesame objects that also exist in themselves. So, on this reading,appearances are not mental representations, and transcendental idealism isnot a form of phenomenalism.[11]

There are at least two main versions of the two-aspects theory. Oneversion treats transcendental idealism as a metaphysical theory accordingto which objects have two aspects in the sense that they have two sets ofproperties: one set of relational properties that appear to us and are spatialand temporal, and another set of intrinsic properties that do not appear tous and are not spatial or temporal (Langton 1998). This property-dualistinterpretation faces epistemological objections similar to those faced bythe two-objects interpretation, because we are in no better position toacquire knowledge about properties that do not appear to us than we areto acquire knowledge about objects that do not appear to us. Moreover,this interpretation also seems to imply that things in themselves are spatialand temporal, since appearances have spatial and temporal properties, andon this view appearances are the same objects as things in themselves. ButKant explicitly denies that space and time are properties of things inthemselves.

A second version of the two-aspects theory departs more radically fromthe traditional two-objects interpretation by denying that transcendental

Immanuel Kant


the traditional two-objects interpretation by denying that transcendentalidealism is at bottom a metaphysical theory. Instead, it interpretstranscendental idealism as a fundamentally epistemological theory thatdistinguishes between two standpoints on the objects of experience: thehuman standpoint, from which objects are viewed relative to epistemicconditions that are peculiar to human cognitive faculties (namely, the apriori forms of our sensible intuition); and the standpoint of an intuitiveintellect, from which the same objects could be known in themselves andindependently of any epistemic conditions (Allison 2004). Human beingscannot really take up the latter standpoint but can form only an emptyconcept of things as they exist in themselves by abstracting from all thecontent of our experience and leaving only the purely formal thought ofan object in general. So transcendental idealism, on this interpretation, isessentially the thesis that we are limited to the human standpoint, and theconcept of a thing in itself plays the role of enabling us to chart theboundaries of the human standpoint by stepping beyond them in abstract(but empty) thought.

One criticism of this epistemological version of the two-aspects theory isthat it avoids the objections to other interpretations by attributing to Kanta more limited project than the text of the Critique warrants. There arepassages that support this reading.[12] But there are also many passages inboth editions of the Critique in which Kant describes appearances asrepresentations in the mind and in which his distinction betweenappearances and things in themselves is given not only epistemologicalbut metaphysical significance.[13] It is unclear whether all of these textsadmit of a single, consistent interpretation.

4. The transcendental deduction

The transcendental deduction is the central argument of the Critique ofPure Reason and one of the most complex and difficult texts in the historyof philosophy. Given its complexity, there are naturally many different

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of philosophy. Given its complexity, there are naturally many differentways of interpreting the deduction.[14] This brief overview provides oneperspective on some of its main ideas.

The transcendental deduction occurs in the part of the Critique called theAnalytic of Concepts, which deals with the a priori concepts that, onKant's view, our understanding uses to construct experience together withthe a priori forms of our sensible intuition (space and time), which hediscussed in the Transcendental Aesthetic. Kant calls these a prioriconcepts “categories,” and he argues elsewhere (in the so-calledmetaphysical deduction) that they include such concepts as substance andcause. The goal of the transcendental deduction is to show that we have apriori concepts or categories that are objectively valid, or that applynecessarily to all objects in the world that we experience. To show this,Kant argues that the categories are necessary conditions of experience, orthat we could not have experience without the categories. In Kant'swords:

The strategy Kant employs to argue that the categories are conditions ofexperience is the main source of both the obscurity and the ingenuity of

[T]he objective validity of the categories, as a priori concepts,rests on the fact that through them alone is experience possible (asfar as the form of thinking is concerned). For they then are relatednecessarily and a priori to objects of experience, since only bymeans of them can any object of experience be thought at all.

The transcendental deduction of all a priori concepts therefore hasa principle toward which the entire investigation must be directed,namely this: that they must be recognized as a priori conditions ofthe possibility of experiences (whether of the intuition that isencountered in them, or of the thinking). Concepts that supply theobjective ground of the possibility of experience are necessary justfor that reason. (A93–94/B126)

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experience is the main source of both the obscurity and the ingenuity ofthe transcendental deduction. His strategy is to argue that the categoriesare necessary specifically for self-consciousness, for which Kant oftenuses the Leibnizian term “apperception.”

4.1 Self-consciousness

One way to approach Kant's argument is to contrast his view of self-consciousness with two alternative views that he rejects. Each of theseviews, both Kant's and those he rejects, can be seen as offering competinganswers the question: what is the source of our sense of an ongoing andinvariable self that persists throughout all the changes in our experience?

The first answer to this question that Kant rejects is that self-consciousness arises from some particular content being present in eachof one’s representations. This material conception of self-consciousness,as we may call it, is loosely suggested by Locke’s account of personalidentity. According to Locke, “it being the same consciousness thatmakes a Man be himself to himself, personal Identity depends on thatonly, whether it be annexed only to one individual Substance, or can becontinued in a succession of several Substances” (Essay 2.27.10). WhatLocke calls “the same consciousness” may be understood as somerepresentational content that is always present in my experience and thatboth identifies any experience as mine and gives me a sense of acontinuous self by virtue of its continual presence in my experience. Oneproblem with this view, Kant believes, is that there is no suchrepresentational content that is invariably present in experience, so thesense of an ongoing self cannot possibly arise from that non-existentcontent (what Locke calls “consciousness”) being present in each of one'srepresentations. In Kant's words, self-consciousness “does not yet comeabout by my accompanying each representation with consciousness, butrather by my adding one representation to the other and being consciousof their synthesis. Therefore it is only because I can combine a manifold

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of their synthesis. Therefore it is only because I can combine a manifoldof given representations in one consciousness that it is possible for me torepresent the identity of the consciousness in these representations”(B133). Here Kant claims, against the Lockean view, that self-consciousness arises from combining (or synthesizing) representationswith one another regardless of their content. In short, Kant has a formalconception of self-consciousness rather than a material one. Since noparticular content of my experience is invariable, self-consciousness mustderive from my experience having an invariable form or structure, andconsciousness of the identity of myself through all of my changingexperiences must consist in awareness of the formal unity and law-governed regularity of my experience. The continuous form of myexperience is the necessary correlate for my sense of a continuous self.

There are at least two possible versions of the formal conception of self-consciousness: a realist and an idealist version. On the realist version,nature itself is law-governed and we become self-conscious by attendingto its law-governed regularities, which also makes this an empiricist viewof self-consciousness. The idea of an identical self that persists throughoutall of our experience, on this view, arises from the law-governedregularity of nature, and our representations exhibit order and regularitybecause reality itself is ordered and regular. But Kant rejects this viewand embraces a conception of self-consciousness that is both formal andidealist. According to Kant, the formal structure of our experience, itsunity and law-governed regularity, is an achievement of our cognitivefaculties rather than a property of reality in itself. Our experience has aconstant form because our mind constructs experience in a law-governedway. So self-consciousness, for Kant, consists in awareness of the mind'slaw-governed activity of synthesizing or combining sensible data toconstruct a unified experience. As he expresses it, “this unity ofconsciousness would be impossible if in the cognition of the manifold themind could not become conscious of the identity of the function by meansof which this manifold is synthetically combined into one cognition”

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of which this manifold is synthetically combined into one cognition”(A108).

Kant argues for this formal idealist conception of self-consciousness, andagainst the formal realist view, on the grounds that “we can representnothing as combined in the object without having previously combined itourselves” (B130). In other words, even if reality in itself were law-governed, its laws could not simply migrate over to our mind or imprintthemselves on us while our mind is entirely passive. We must exercise anactive capacity to represent the world as combined or ordered in a law-governed way, because otherwise we could not represent the world aslaw-governed even if it were law-governed in itself. Moreover, thiscapacity to represent the world as law-governed must be a priori becauseit is a condition of self-consciousness, and we would already have to beself-conscious in order to learn from our experience that there are law-governed regularities in the world. So it is necessary for self-consciousness that we exercise an a priori capacity to represent the worldas law-governed. But this would also be sufficient for self-consciousnessif we could exercise our a priori capacity to represent the world as law-governed even if reality in itself were not law-governed. In that case, therealist and empiricist conception of self-consciousness would be false, andthe formal idealist view would be true.

Kant's confidence that no empiricist account could possibly explain self-consciousness may be based on his assumption that the sense of self eachof us has, the thought of oneself as identical throughout all of one'schanging experiences, involves necessity and universality, which on hisview are the hallmarks of the a priori. This assumption is reflected inwhat we may call Kant's principle of apperception: “The I think must beable to accompany all my representations; for otherwise something wouldbe represented in me that could not be thought at all, which is as much asto say that the representation would either be impossible or else at least

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would be nothing for me” (B131–132).[15] Notice the claims aboutnecessity and universality embodied in the words “must” and “all” here.Kant is saying that for a representation to count as mine, it mustnecessarily be accessible to conscious awareness in some (perhapsindirect) way: I must be able to accompany it with “I think....” All of myrepresentations must be accessible to consciousness in this way (but theyneed not actually be conscious), because again that is simply what makesa representation count as mine. Self-consciousness for Kant thereforeinvolves a priori knowledge about the necessary and universal truthexpressed in this principle of apperception, and a priori knowledge cannotbe based on experience.

4.2 Objectivity and judgment

On the basis of this formal idealist conception of self-consciousness,Kant's argument (at least one central thread of it) moves through twomore conditions of self-consciousness in order to establish the objectivevalidity of the categories. The next condition is that self-consciousnessrequires me to represent an objective world distinct from my subjectiverepresentations - that is, distinct from my thoughts about and sensations ofthat objective world. Kant uses this connection between self-consciousness and objectivity to insert the categories into his argument.

In order to be self-conscious, I cannot be wholly absorbed in the contentsof my perceptions but must distinguish myself from the rest of the world.But if self-consciousness is an achievement of the mind, then how doesthe mind achieve this sense that there is a distinction between the I thatperceives and the contents of its perceptions? According to Kant, themind achieves this by distinguishing representations that necessarilybelong together from representations that are not necessarily connectedbut are merely associated in a contingent way. Consider Kant's exampleof the perception of a house (B162). Imagine a house that is too large tofit into your visual field from your vantage point near its front door. Now

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fit into your visual field from your vantage point near its front door. Nowimagine that you walk around the house, successively perceiving each ofits sides. Eventually you perceive the entire house, but not all at once, andyou judge that each of your representations of the sides of the housenecessarily belong together (as sides of one house) and that anyone whodenied this would be mistaken. But now imagine that you grew up in thishouse and associate a feeling of nostalgia with it. You would not judgethat representations of this house are necessarily connected with feelingsof nostalgia. That is, you would not think that other people seeing thehouse for the first time would be mistaken if they denied that it isconnected with nostalgia, because you recognize that this house isconnected with nostalgia for you but not necessarily for everyone. Yetyou distinguish this merely subjective connection from the objectiveconnection between sides of the house, which is objective because thesides of the house necessarily belong together “in the object,” because thisconnection holds for everyone universally, and because it is possible to bemistaken about it. The point here is not that we must successfully identifywhich representations necessarily belong together and which are merelyassociated contingently, but rather that to be self-conscious we must atleast make this general distinction between objective and merelysubjective connections of representations.

At this point (at least in the second edition text) Kant introduces the keyclaim that judgment is what enables us to distinguish objectiveconnections of representations that necessarily belong together frommerely subjective and contingent associations: “[A] judgment is nothingother than the way to bring given cognitions to the objective unity ofapperception. That is the aim of the copula is in them: to distinguish theobjective unity of given representations from the subjective. For this worddesignates the relation of the representations to the original apperceptionand its necessary unity” (B141–142). Kant is speaking here about themental act of judging that results in the formation of a judgment. Judgingis an act of what Kant calls synthesis, which he defines as “the action of

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is an act of what Kant calls synthesis, which he defines as “the action ofputting different representations together with each other andcomprehending their manifoldness in one cognition” (A77/B103). In otherwords, to synthesize is in general to combine several representations intoa single (more) complex representation, and to judge is specifically tocombine concepts into a judgment — that is, to join a subject concept to apredicate concept by means of the copula, as in “the body is heavy” or“the house is four-sided.” Judgments need not be true, of course, but theyalways have a truth value (true or false) because they make claims toobjective validity. When I say, by contrast, that “If I carry a body, I feel apressure of weight,” or that “if I see this house, I feel nostalgia,” I am notmaking a judgment about the object (the body or the house) but rather Iam expressing a subjective association that may apply only to me(B142).[16]

Kant's reference to the necessary unity of apperception or self-consciousness in the quotation above means (at least) that the action ofjudging is the way our mind achieves self-consciousness. We mustrepresent an objective world in order to distinguish ourselves from it, andwe represent an objective world by judging that some representationsnecessarily belong together. Moreover, recall from 4.1 that, for Kant, wemust have an a priori capacity to represent the world as law-governed,because “we can represent nothing as combined (or connected) in theobject without having previously combined it ourselves” (B130). Itfollows that objective connections in the world cannot simply imprintthemselves on our mind. Rather, experience of an objective world must beconstructed by exercising an a priori capacity to judge, which Kant callsthe faculty of understanding (A80–81/B106). The understandingconstructs experience by providing the a priori rules, or the framework ofnecessary laws, in accordance with which we judge representations to beobjective. These rules are the pure concepts of the understanding orcategories, which are therefore conditions of self-consciousness, sincethey are rules for judging about an objective world, and self-

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they are rules for judging about an objective world, and self-consciousness requires that we distinguish ourselves from an objectiveworld.

Kant identifies the categories in what he calls the metaphysical deduction,which precedes the transcendental deduction.[17] Very briefly, since thecategories are a priori rules for judging, Kant argues that an exhaustivetable of categories can be derived from a table of the basic logical formsof judgments. For example, according to Kant the logical form of thejudgment that “the body is heavy” would be singular, affirmative,categorical, and assertoric. But since categories are not mere logicalfunctions but instead are rules for making judgments about objects or anobjective world, Kant arrives at his table of categories by consideringhow each logical function would structure judgments about objects(within our spatio-temporal forms of intuition). For example, he claimsthat categorical judgments express a logical relation between subject andpredicate that corresponds to the ontological relation between substanceand accident; and the logical form of a hypothetical judgment expresses arelation that corresponds to cause and effect. Taken together with thisargument, then, the transcendental deduction argues that we become self-conscious by representing an objective world of substances that interactaccording to causal laws.

4.3 The law-giver of nature

The final condition of self-consciousness that Kant adds to the precedingconditions is that our understanding must cooperate with sensibility toconstruct one, unbounded, and unified space-time to which all of ourrepresentations may be related.

To see why this further condition is required, consider that so far we haveseen why Kant holds that we must represent an objective world in orderto be self-conscious, but we could represent an objective world even if it

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to be self-conscious, but we could represent an objective world even if itwere not possible to relate all of our representations to this objectiveworld. For all that has been said so far, we might still have unrulyrepresentations that we cannot relate in any way to the objectiveframework of our experience. On Kant's view, this would be a problembecause, as we have seen, he holds that self-consciousness involvesuniversality and necessity: according to his principle of apperception, “theI think must be able to accompany all my representations” (B131). Yet if,on the one hand, I had representations that I could not relate in some wayto an objective world, then I could not accompany those representationswith “I think” or recognize them as my representations, because I can say“I think…” about any given representation only by relating it to anobjective world, according to the argument just discussed. So I must beable to relate any given representation to an objective world in order for itto count as mine. On the other hand, self-consciousness would also beimpossible if I represented multiple objective worlds, even if I couldrelate all of my representations to some objective world or other. In thatcase, I could not become conscious of an identical self that has, say,representation 1 in space-time A and representation 2 in space-time B. Itmay be possible to imagine disjointed spaces and times, but it is notpossible to represent them as objectively real. So self-consciousnessrequires that I can relate all of my representations to a single objectiveworld.

The reason why I must represent this one objective world by means of aunified and unbounded space-time is that, as Kant argued in theTranscendental Aesthetic, space and time are the pure forms of humanintuition. If we had different forms of intuition, then our experience wouldstill have to constitute a unified whole in order for us to be self-conscious,but this would not be a spatio-temporal whole. Given that space and timeare our forms of intuition, however, our understanding must stillcooperate with sensibility to construct a spatio-temporal whole ofexperience because, once again, “we can represent nothing as combined

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experience because, once again, “we can represent nothing as combinedin the object without having previously combined it ourselves,” and “allcombination [...] is an action of the understanding” (B130). So Kantdistinguishes between space and time as pure forms of intuition, whichbelong solely to sensibility; and the formal intuitions of space and time(or space-time), which are unified by the understanding (B160–161).These formal intuitions are the spatio-temporal whole within which ourunderstanding constructs experience in accordance with thecategories.[18]

The most important implication of Kant's claim that the understandingconstructs a single whole of experience to which all of our representationscan be related is that, since he defines nature “regarded materially” as “thesum total of all appearances” and he has argued that the categories areobjectively valid of all possible appearances, on his view it follows thatour categories are the source of the fundamental laws of nature “regardedformally” (B163, 165). So Kant concludes on this basis that theunderstanding is the true law-giver of nature. In his words: “allappearances in nature, as far as their combination is concerned, standunder the categories, on which nature (considered merely as nature ingeneral) depends, as the original ground of its necessary lawfulness (asnature regarded formally)” (ibid.). Or more strongly: “we ourselves bringinto the appearances that order and regularity that we call nature, andmoreover we would not be able to find it there if we, or the nature of ourmind, had not originally put it there. [...] The understanding is thus notmerely a faculty for making rules through the comparison of theappearances: it is itself the legislation for nature, i.e., withoutunderstanding there would not be any nature at all” (A125–126).

5. Morality and freedom

Having examined two central parts of Kant's positive project in theoreticalphilosophy from the Critique of Pure Reason, transcendental idealism and

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philosophy from the Critique of Pure Reason, transcendental idealism andthe transcendental deduction, let us now turn to his practical philosophy inthe Critique of Practical Reason. Since Kant's philosophy is deeplysystematic, this section begins with a preliminary look at how histheoretical and practical philosophy fit together (see also section 7).

5.1 Theoretical and practical autonomy

The fundamental idea of Kant's philosophy is human autonomy. So farwe have seen this in Kant's constructivist view of experience, according towhich our understanding is the source of the general laws of nature.“Autonomy” literally means giving the law to oneself, and on Kant's viewour understanding provides laws that constitute the a priori framework ofour experience. Our understanding does not provide the matter or contentof our experience, but it does provide the basic formal structure withinwhich we experience any matter received through our senses. Kant'scentral argument for this view is the transcendental deduction, accordingto which it is a condition of self-consciousness that our understandingconstructs experience in this way. So we may call self-consciousness thehighest principle of Kant's theoretical philosophy, since it is (at least) thebasis for all of our a priori knowledge about the structure of nature.

Kant's moral philosophy is also based on the idea of autonomy. He holdsthat there is a single fundamental principle of morality, on which allspecific moral duties are based. He calls this moral law (as it ismanifested to us) the categorical imperative (see 5.4). The moral law is aproduct of reason, for Kant, while the basic laws of nature are products ofour understanding. There are important differences between the senses inwhich we are autonomous in constructing our experience and in morality.For example, Kant regards understanding and reason as differentcognitive faculties, although he sometimes uses “reason” in a wide senseto cover both.[19] The categories and therefore the laws of nature aredependent on our specifically human forms of intuition, while reason is

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dependent on our specifically human forms of intuition, while reason isnot. The moral law does not depend on any qualities that are peculiar tohuman nature but only on the nature of reason as such, although itsmanifestation to us as a categorical imperative (as a law of duty) reflectsthe fact that the human will is not necessarily determined by pure reasonbut is also influenced by other incentives rooted in our needs andinclinations; and our specific duties deriving from the categoricalimperative do reflect human nature and the contingencies of human life.Despite these differences, however, Kant holds that we give the moral lawto ourselves, just as we also give the general laws of nature to ourselves,though in a different sense. Moreover, we each necessarily give the samemoral law to ourselves, just as we each construct our experience inaccordance with the same categories. To summarize:

Theoretical philosophy is about how the world is (A633/B661). Itshighest principle is self-consciousness, on which our knowledge ofthe basic laws of nature is based. Given sensory data, ourunderstanding constructs experience according to these a priori laws.Practical philosophy is about how the world ought to be (ibid.,A800–801/B828–829). Its highest principle is the moral law, fromwhich we derive duties that command how we ought to act inspecific situations. Kant also claims that reflection on our moralduties and our need for happiness leads to the thought of an idealworld, which he calls the highest good (see section 6). Given howthe world is (theoretical philosophy) and how it ought to be(practical philosophy), we aim to make the world better byconstructing or realizing the highest good.

So both parts of Kant's philosophy are about autonomously constructing aworld, but in different senses. In theoretical philosophy, we use ourcategories and forms of intuition to construct a world of experience ornature. In practical philosophy, we use the moral law to construct the ideaof a moral world or a realm of ends that guides our conduct (4:433), and

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of a moral world or a realm of ends that guides our conduct (4:433), andultimately to transform the natural world into the highest good. Finally,transcendental idealism is the framework within which these two parts ofKant's philosophy fit together (20:311). Theoretical philosophy deals withappearances, to which our knowledge is strictly limited; and practicalphilosophy deals with things in themselves, although it does not give usknowledge about things in themselves but only provides rationaljustification for certain beliefs about them for practical purposes.

To understand Kant's arguments that practical philosophy justifies certainbeliefs about things in themselves, it is necessary to see them in thecontext of his criticism of German rationalist metaphysics. The threetraditional topics of Leibniz-Wolffian special metaphysics were rationalpsychology, rational cosmology, and rational theology, which dealt,respectively, with the human soul, the world-whole, and God. In the partof the Critique of Pure Reason called the Transcendental Dialectic, Kantargues against the Leibniz-Wolffian view that human beings are capableof a priori knowledge in each of these domains, and he claims that theerrors of Leibniz-Wolffian metaphysics are due to an illusion that has itsseat in the nature of human reason itself. According to Kant, humanreason necessarily produces ideas of the soul, the world-whole, and God;and these ideas unavoidably produce the illusion that we have a prioriknowledge about transcendent objects corresponding to them. This is anillusion, however, because in fact we are not capable of a prioriknowledge about any such transcendent objects. Nevertheless, Kantattempts to show that these illusory ideas have a positive, practical use.He thus reframes Leibniz-Wolffian special metaphysics as a practicalscience that he calls the metaphysics of morals. On Kant's view, our ideasof the soul, the world-whole, and God provide the content of morallyjustified beliefs about human immortality, human freedom, and theexistence of God, respectively; but they are not proper objects ofspeculative knowledge.[20]

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5.2 Freedom

The most important belief about things in themselves that Kant thinksonly practical philosophy can justify concerns human freedom. Freedomis important because, on Kant's view, moral appraisal presupposes that weare free in the sense that we have the ability to do otherwise. To see why,consider Kant's example of a man who commits a theft (5:95ff.). Kantholds that in order for this man's action to be morally wrong, it must havebeen within his control in the sense that it was within his power at thetime not to have committed the theft. If this was not within his control atthe time, then, while it may be useful to punish him in order to shape hisbehavior or to influence others, it nevertheless would not be correct to saythat his action was morally wrong. Moral rightness and wrongness applyonly to free agents who control their actions and have it in their power, atthe time of their actions, either to act rightly or not. According to Kant,this is just common sense.

On these grounds, Kant rejects a type of compatibilism that he calls the“comparative concept of freedom” and associates with Leibniz (5:96–97).(Note that Kant has a specific type of compatibilism in mind, which I willrefer to simply as “compatibilism,” although there may be other types ofcompatibilism that do not fit Kant's characterization of that view). On thecompatibilist view, as Kant understands it, I am free whenever the causeof my action is within me. So I am unfree only when something externalto me pushes or moves me, but I am free whenever the proximate causeof my body's movement is internal to me as an “acting being” (5:96). Ifwe distinguish between involuntary convulsions and voluntary bodilymovements, then on this view free actions are just voluntary bodilymovements. Kant ridicules this view as a “wretched subterfuge” that triesto solve an ancient philosophical problem “with a little quibbling aboutwords” (ibid.). This view, he says, assimilates human freedom to “thefreedom of a turnspit,” or a projectile in flight, or the motion of a clock's

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freedom of a turnspit,” or a projectile in flight, or the motion of a clock'shands (5:96–97). The proximate causes of these movements are internalto the turnspit, the projectile, and the clock at the time of the movement.This cannot be sufficient for moral responsibility.

Why not? The reason, Kant says, is ultimately that the causes of thesemovements occur in time. Return to the theft example. A compatibilistwould say that the thief's action is free because its proximate cause isinside him, and because the theft was not an involuntary convulsion but avoluntary action. The thief decided to commit the theft, and his actionflowed from this decision. According to Kant, however, if the thief'sdecision is a natural phenomenon that occurs in time, then it must be theeffect of some cause that occurred in a previous time. This is an essentialpart of Kant's Newtonian worldview and is grounded in the a priori laws(specifically, the category of cause and effect) in accordance with whichour understanding constructs experience: every event has a cause thatbegins in an earlier time. If that cause too was an event occurring in time,then it must also have a cause beginning in a still earlier time, etc. Allnatural events occur in time and are thoroughly determined by causalchains that stretch backwards into the distant past. So there is no room forfreedom in nature, which is deterministic in a strong sense.

The root of the problem, for Kant, is time. Again, if the thief's choice tocommit the theft is a natural event in time, then it is the effect of a causalchain extending into the distant past. But the past is out of his controlnow, in the present. Once the past is past, he can't change it. On Kant'sview, that is why his actions would not be in his control in the present ifthey are determined by events in the past. Even if he could control thosepast events in the past, he cannot control them now. But in fact pastevents were not in his control in the past either if they too weredetermined by events in the more distant past, because eventually thecausal antecedents of his action stretch back before his birth, andobviously events that occurred before his birth were not in his control. So

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obviously events that occurred before his birth were not in his control. Soif the thief's choice to commit the theft is a natural event in time, then itis not now and never was in his control, and he could not have doneotherwise than to commit the theft. In that case, it would be a mistake tohold him morally responsible for it.

Compatibilism, as Kant understands it, therefore locates the issue in thewrong place. Even if the cause of my action is internal to me, if it is inthe past — for example, if my action today is determined by a decision Imade yesterday, or from the character I developed in childhood — then itis not within my control now. The real issue is not whether the cause ofmy action is internal or external to me, but whether it is in my controlnow. For Kant, however, the cause of my action can be within my controlnow only if it is not in time. This is why Kant thinks that transcendentalidealism is the only way to make sense of the kind of freedom thatmorality requires. For transcendental idealism allows that the cause of myaction may be a thing in itself outside of time: namely, my noumenal self,which is free because it is not part of nature. No matter what kind ofcharacter I have developed or what external influences act on me, onKant's view all of my intentional, voluntary actions are immediate effectsof my noumenal self, which is causally undetermined (5:97–98). Mynoumenal self is an uncaused cause outside of time, which therefore is notsubject to the deterministic laws of nature in accordance with which ourunderstanding constructs experience.

Many puzzles arise on this picture that Kant does not resolve. Forexample, if my understanding constructs all appearances in my experienceof nature, not only appearances of my own actions, then why am Iresponsible only for my own actions but not for everything that happensin the natural world? Moreover, if I am not alone in the world but thereare many noumenal selves acting freely and incorporating their freeactions into the experience they construct, then how do multipletranscendentally free agents interact? How do you integrate my free

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transcendentally free agents interact? How do you integrate my freeactions into the experience that your understanding constructs?[21] Inspite of these unsolved puzzles, Kant holds that we can make sense ofmoral appraisal and responsibility only by thinking about human freedomin this way, because it is the only way to prevent natural necessity fromundermining both.

Finally, since Kant invokes transcendental idealism to make sense offreedom, interpreting his thinking about freedom leads us back to disputesbetween the two-objects and two-aspects interpretations of transcendentalidealism. On the face of it, the two-objects interpretation seems to makebetter sense of Kant's view of transcendental freedom than the two-aspects interpretation. If morality requires that I am transcendentally free,then it seems that my true self, and not just an aspect of my self, must beoutside of time, according to Kant's argument. But applying the two-objects interpretation to freedom raises problems of its own, since itinvolves making a distinction between noumenal and phenomenal selvesthat does not arise on the two-aspects view. If only my noumenal self isfree, and freedom is required for moral responsibility, then myphenomenal self is not morally responsible. But how are my noumenaland phenomenal selves related, and why is punishment inflicted onphenomenal selves? It is unclear whether and to what extent appealing toKant's theory of freedom can help to settle disputes about the properinterpretation of transcendental idealism, since there are serious questionsabout the coherence of Kant's theory on either interpretation.

5.3 The fact of reason

Can we know that we are free in this transcendental sense? Kant'sresponse is tricky. On the one hand, he distinguishes between theoreticalknowledge and morally justified belief (A820–831/B848–859). We do nothave theoretical knowledge that we are free or about anything beyond thelimits of possible experience, but we are morally justified in believing

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limits of possible experience, but we are morally justified in believingthat we are free in this sense. On the other hand, Kant also uses strongerlanguage than this when discussing freedom. For example, he says that“among all the ideas of speculative reason freedom is the only one thepossibility of which we know a priori, though without having any insightinto it, because it is the condition of the moral law, which we do know.”In a footnote to this passage, Kant explains that we know freedom a prioribecause “were there no freedom, the moral law would not be encounteredat all in ourselves,” and on Kant's view everyone does encounter themoral law a priori (5:4). For this reason, Kant claims that the moral law“proves” the objective, “though only practical, undoubted reality” offreedom (5:48–49). So Kant wants to say that we do have knowledge ofthe reality of freedom, but that this is practical knowledge of a practicalreality, or cognition “only for practical purposes,” by which he means todistinguish it from theoretical knowledge based on experience orreflection on the conditions of experience (5:133). Our practicalknowledge of freedom is based instead on the moral law. The differencebetween Kant's stronger and weaker language seems mainly to be that hisstronger language emphasizes that our belief or practical knowledge aboutfreedom is unshakeable and that it in turn provides support for othermorally grounded beliefs in God and the immortality of the soul.

Kant calls our consciousness of the moral law, our awareness that themoral law binds us or has authority over us, the “fact of reason” (5:31–32,42–43, 47, 55). So, on his view, the fact of reason is the practical basis forour belief or practical knowledge that we are free. Kant insists that thismoral consciousness is “undeniable,” “a priori,” and “unavoidable” (5:32,47, 55). Every human being has a conscience, a common sense grasp ofmorality, and a firm conviction that he or she is morally accountable. Wemay have different beliefs about the source of morality's authority —God, social convention, human reason. We may arrive at differentconclusions about what morality requires in specific situations. And wemay violate our own sense of duty. But we all have a conscience, and an

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may violate our own sense of duty. But we all have a conscience, and anunshakeable belief that morality applies to us. According to Kant, thisbelief cannot and does not need to be justified or “proved by anydeduction” (5:47). It is just a ground-level fact about human beings thatwe hold ourselves morally accountable. But Kant is making a normativeclaim here as well: it is also a fact, which cannot and does not need to bejustified, that we are morally accountable, that morality does haveauthority over us. Kant holds that philosophy should be in the business ofdefending this common sense moral belief, and that in any case it couldnever prove or disprove it (4:459).

Kant may hold that the fact of reason, or our consciousness of moralobligation, implies that we are free on the grounds that ought implies can.In other words, Kant may believe that it follows from the fact that weought (morally) to do something that we can or are able to do it. This issuggested, for example, by a passage in which Kant asks us to imaginesomeone threatened by his prince with immediate execution unless he“give[s] false testimony against an honorable man whom the prince wouldlike to destroy under a plausible pretext.” Kant says that “[h]e wouldperhaps not venture to assert whether he would do it or not, but he mustadmit without hesitation that it would be possible for him. He judges,therefore, that he can do something because he is aware that he ought todo it and cognizes freedom within him, which, without the moral law,would have remained unknown to him” (5:30). This is a hypotheticalexample of an action not yet carried out. It seems that pangs of guilt aboutthe immorality of an action that you carried out in the past, on thisreasoning, would imply more directly that you have (or at least had) theability to act otherwise than you did, and therefore that you are free inKant's sense.

Immanuel Kant


5.4 The categorical imperative

In both the Groundwork of the Metaphysics of Morals and the Critique ofPractical Reason, Kant also gives a more detailed argument for theconclusion that morality and freedom reciprocally imply one another,which is sometimes called the reciprocity thesis (Allison 1990). On thisview, to act morally is to exercise freedom, and the only way to fullyexercise freedom is to act morally. Kant's arguments for this view differin these texts, but the general structure of his argument in the Critique ofPractical Reason may be summarized as follows.

First, it follows from the basic idea of having a will that to act at all is toact on some principle, or what Kant calls a maxim. A maxim is asubjective rule or policy of action: it says what you are doing and why.Kant gives as examples the maxims “to let no insult pass unavenged” and“to increase my wealth by every safe means” (5:19, 27). We may beunaware of our maxims, we may not act consistently on the samemaxims, and our maxims may not be consistent with one another. ButKant holds that since we are rational beings our actions always aim atsome sort of end or goal, which our maxim expresses. The goal of anaction may be something as basic as gratifying a desire, or it may besomething more complex such as becoming a doctor or a lawyer. In anycase, the causes of our actions are never our desires or impulses, onKant's view. If I act to gratify some desire, then I choose to act on amaxim that specifies the gratification of that desire as the goal of myaction. For example, if I desire some coffee, then I may act on the maximto go to a cafe and buy some coffee in order to gratify that desire.

Second, Kant distinguishes between two basic kinds of principles or rulesthat we can act on: what he calls material and formal principles. To act inorder to satisfy some desire, as when I act on the maxim to go for coffeeat a cafe, is to act on a material principle (5:21ff.). Here the desire (forcoffee) fixes the goal, which Kant calls the object or matter of the action,

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coffee) fixes the goal, which Kant calls the object or matter of the action,and the principle says how to achieve that goal (go to a cafe).Corresponding to material principles, on Kant's view, are what he callshypothetical imperatives. A hypothetical imperative is a principle ofrationality that says that I should act in a certain way if I choose to satisfysome desire. If maxims in general are rules that describe how one doesact, then imperatives in general prescribe how one should act. Animperative is hypothetical if it says how I should act only if I choose topursue some goal in order to gratify a desire (5:20). This, for example, isa hypothetical imperative: if you want coffee, then go to the cafe. Thishypothetical imperative applies to you only if you desire coffee andchoose to gratify that desire.

In contrast to material principles, formal principles describe how one actswithout making reference to any desires. This is easiest to understandthrough the corresponding kind of imperative, which Kant calls acategorical imperative. A categorical imperative commandsunconditionally that I should act in some way. So while hypotheticalimperatives apply to me only on the condition that I have and set the goalof satisfying the desires that they tell me how to satisfy, categoricalimperatives apply to me no matter what my goals and desires may be.Kant regards moral laws as categorical imperatives, which apply toeveryone unconditionally. For example, the moral requirement to helpothers in need does not apply to me only if I desire to help others in need,and the duty not to steal is not suspended if I have some desire that Icould satisfy by stealing. Moral laws do not have such conditions butrather apply unconditionally. That is why they apply to everyone in thesame way.

Third, insofar as I act only on material principles or hypotheticalimperatives, I do not act freely, but rather I act only to satisfy somedesire(s) that I have, and what I desire is not ultimately within my control.To some limited extent we are capable of rationally shaping our desires,

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To some limited extent we are capable of rationally shaping our desires,but insofar as we choose to act in order to satisfy desires we are choosingto let nature govern us rather than governing ourselves (5:118). We arealways free in the sense that we always have the capacity to governourselves rationally instead of letting our desires set our ends for us. Butwe may (freely) fail to exercise that capacity. Moreover, since Kant holdsthat desires never cause us to act, but rather we always choose to act on amaxim even when that maxim specifies the satisfaction of a desire as thegoal of our action, it also follows that we are always free in the sense thatwe freely choose our maxims. Nevertheless, our actions are not free in thesense of being autonomous if we choose to act only on materialprinciples, because in that case we do not give the law to ourselves, butinstead we choose to allow nature in us (our desires) to determine the lawfor our actions.

Finally, the only way to act freely in the full sense of exercisingautonomy is therefore to act on formal principles or categoricalimperatives, which is also to act morally. Kant does not mean that actingautonomously requires that we take no account of our desires, becausethat would be impossible (5:25, 61). Rather, he holds that we typicallyformulate maxims with a view to satisfying our desires, but that “as soonas we draw up maxims of the will for ourselves” we become immediatelyconscious of the moral law (5:29). This immediate consciousness of themoral law takes the following form:

I have, for example, made it my maxim to increase my wealth byevery safe means. Now I have a deposit in my hands, the owner ofwhich has died and left no record of it. This is, naturally, a casefor my maxim. Now I want only to know whether that maximcould also hold as a universal practical law. I therefore apply themaxim to the present case and ask whether it could indeed takethe form of a law, and consequently whether I could through mymaxim at the same time give such a law as this: that everyone may

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In other words, to assess the moral permissibility of my maxim, I askwhether everyone could act on it, or whether it could be willed as auniversal law. The issue is not whether it would be good if everyoneacted on my maxim, or whether I would like it, but only whether it wouldbe possible for my maxim to be willed as a universal law. This gets at theform, not the matter or content, of the maxim. A maxim has morallypermissible form, for Kant, only if it could be willed as a universal law. Ifmy maxim fails this test, as this one does, then it is morally impermissiblefor me to act on it.

If my maxim passes the universal law test, then it is morally permissiblefor me to act on it, but I fully exercise my autonomy only if myfundamental reason for acting on this maxim is that it is morallypermissible or required that I do so. Imagine that I am moved by a feelingof sympathy to formulate the maxim to help someone in need. In thiscase, my original reason for formulating this maxim is that a certainfeeling moved me. Such feelings are not entirely within my control andmay not be present when someone actually needs my help. But thismaxim passes Kant's test: it could be willed as a universal law thateveryone help others in need from motives of sympathy. So it would notbe wrong to act on this maxim when the feeling of sympathy so movesme. But helping others in need would not fully exercise my autonomyunless my fundamental reason for doing so is not that I have some feelingor desire, but rather that it would be right or at least permissible to do so.Only when such a purely formal principle supplies the fundamentalmotive for my action do I act autonomously.

maxim at the same time give such a law as this: that everyone maydeny a deposit which no one can prove has been made. I at oncebecome aware that such a principle, as a law, would annihilateitself since it would bring it about that there would be no depositsat all. (5:27)

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So the moral law is a law of autonomy in the sense that “freedom andunconditional practical law reciprocally imply each another” (5:29). Evenwhen my maxims are originally suggested by my feelings and desires, if Iact only on morally permissible (or required) maxims because they aremorally permissible (or required), then my actions will be autonomous.And the reverse is true as well: for Kant this is the only way to actautonomously.[22]

6. The highest good and practical postulates

Kant holds that reason unavoidably produces not only consciousness ofthe moral law but also the idea of a world in which there is both completevirtue and complete happiness, which he calls the highest good. Our dutyto promote the highest good, on Kant's view, is the sum of all moralduties, and we can fulfill this duty only if we believe that the highest goodis a possible state of affairs. Furthermore, we can believe that the highestgood is possible only if we also believe in the immortality of the soul andthe existence of God, according to Kant. On this basis, he claims that it ismorally necessary to believe in the immortality of the soul and theexistence of God, which he calls postulates of pure practical reason. Thissection briefly outlines Kant's view of the highest good and his argumentfor these practical postulates in the Critique of Practical Reason and otherworks.

6.1 The highest good

In the previous section we saw that, on Kant's view, the moral law is apurely formal principle that commands us to act only on maxims thathave what he calls lawgiving form, which maxims have only if they canbe willed as universal laws. Moreover, our fundamental reason forchoosing to act on such maxims should be that they have this lawgivingform, rather than that acting on them would achieve some end or goal thatwould satisfy a desire (5:27). For example, I should help others in need

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would satisfy a desire (5:27). For example, I should help others in neednot, at bottom, because doing so would make me feel good, even if itwould, but rather because it is right; and it is right (or permissible) to helpothers in need because this maxim can be willed as a universal law.

But although Kant holds that the morality of an action depends on theform of its maxim rather than its end or goal, he nevertheless claims boththat every human action has an end and that we are unavoidablyconcerned with the consequences of our actions (4:437; 5:34; 6:5–7, 385).This is not a moral requirement but simply part of what it means to be arational being. Moreover, Kant also holds the stronger view that it is anunavoidable feature of human reason that we form ideas not only aboutthe immediate and near-term consequences of our actions, but also aboutultimate consequences. This is the practical manifestation of reason'sgeneral demand for what Kant calls “the unconditioned” (5:107–108).[23]

In particular, since we naturally have desires and inclinations, and ourreason has “a commission” to attend to the satisfaction of our desires andinclinations, on Kant's view we unavoidably form an idea of the maximalsatisfaction of all our inclinations and desires, which he calls happiness(5:61, 22, 124). This idea is indeterminate, however, since nobody canknow “what he really wishes and wills” and thus what would make himcompletely happy (4:418). We also form the idea of a moral world orrealm of ends, in which everyone acts only in accordance with maximsthat can be universal laws (A808/B836, 4:433ff.).

But neither of these ideas by itself expresses our unconditionally completeend, as human reason demands in its practical use. A perfectly moralworld by itself would not constitute our “whole and complete good [...]even in the judgment of an impartial reason,” because it is human naturealso to need happiness (5:110, 25). And happiness by itself would not beunconditionally good, because moral virtue is a condition of worthiness tobe happy (5:111). So our unconditionally complete end must combineboth virtue and happiness. In Kant's words, “virtue and happiness together

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both virtue and happiness. In Kant's words, “virtue and happiness togetherconstitute possession of the highest good in a person, and happinessdistributed in exact proportion to morality (as the worth of a person andhis worthiness to be happy) constitutes the highest good of a possibleworld” (5:110–111). It is this ideal world combining complete virtue withcomplete happiness that Kant normally has in mind when he discusses thehighest good.

Kant says that we have a duty to promote the highest good, taken in thissense (5:125). He does not mean, however, to be identifying some newduty that is not derived from the moral law, in addition to all theparticular duties we have that are derived from the moral law.[24] Forexample, he is not claiming that in addition to my duties to help others inneed, not to commit theft, etc., I also have the additional duty to representthe highest good as the final end of all moral conduct, combined withhappiness, and to promote that end. Rather, as we have seen, Kant holdsthat it is an unavoidable feature of human reasoning, instead of a moralrequirement, that we represent all particular duties as leading toward thepromotion of the highest good. So the duty to promote the highest good isnot a particular duty at all, but the sum of all our duties derived from themoral law — it “does not increase the number of morality's duties butrather provides these with a special point of reference for the unificationof all ends” (6:5). Nor does Kant mean that anyone has a duty to realizeor actually bring about the highest good through their own power,although his language sometimes suggests this (5:113, 122). Rather, atleast in his later works Kant claims that only the common striving of anentire “ethical community” can actually produce the highest good, andthat the duty of individuals is to promote (but not single-handedlyproduce) this end with all of their strength by doing what the moral lawcommands (6:97–98, 390–394).[25]

Finally, according to Kant we must conceive of the highest good as apossible state of affairs in order to fulfill our duty to promote it. Here

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possible state of affairs in order to fulfill our duty to promote it. HereKant does not mean that we unavoidably represent the highest good aspossible, since his view is that we must represent it as possible only if weare to do our duty of promoting it, and yet we may fail at doing our duty.Rather, we have a choice about whether to conceive of the highest goodas possible, to regard it as impossible, or to remain noncommittal (5:144–145). But we can fulfill our duty of promoting the highest good only bychoosing to conceive of the highest good as possible, because we cannotpromote any end without believing that it is possible to achieve that end(5:122). So fulfilling the sum of all moral duties to promote the highestgood requires believing that a world of complete virtue and happiness isnot simply “a phantom of the mind” but could actually be realized(5:472).

6.2 The postulates of pure practical reason

Kant argues that we can comply with our duty to promote the highestgood only if we believe in the immortality of the soul and the existence ofGod. This is because to comply with that duty we must believe that thehighest good is possible, and yet to believe that the highest good ispossible we must believe that the soul is immortal and that God exists,according to Kant.[26]

Consider first Kant's moral argument for belief in immortality. Thehighest good, as we have seen, would be a world of complete moralityand happiness. But Kant holds that it is impossible for “a rational being ofthe sensible world” to exhibit “complete conformity of dispositions withthe moral law,” which he calls “holiness,” because we can never extirpatethe propensity of our reason to give priority to the incentives ofinclination over the incentive of duty, which propensity Kant calls radicalevil (5:122, 6:37). But Kant claims that the moral law neverthelessrequires holiness, and that it therefore “can only be found in an endlessprogress toward that complete conformity,” or progress that goes to

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progress toward that complete conformity,” or progress that goes toinfinity (5:122). This does not mean that we can substitute endlessprogress toward complete conformity with the moral law for holiness inthe concept of the highest good, but rather that we must represent thatcomplete conformity as an infinite progress toward the limit of holiness.Kant continues: “This endless progress is, however, possible only on thepresupposition of the existence and personality of the same rational beingcontinuing endlessly (which is called the immortality of the soul). Hencethe highest good is practically possible only on the presupposition of theimmortality of the soul, so that this, as inseparable with the moral law, isa postulate of pure practical reason” (ibid.). Kant's idea is not that weshould imagine ourselves attaining holiness later although we are notcapable of it in this life. Rather, his view is that we must representholiness as continual progress toward complete conformity of ourdispositions with the moral law that begins in this life and extends intoinfinity.

Kant's moral argument for belief in God in the Critique of PracticalReason may be summarized as follows. Kant holds that virtue andhappiness are not just combined but necessarily combined in the idea ofthe highest good, because only possessing virtue makes one worthy ofhappiness — a claim that Kant seems to regard as part of the content ofthe moral law (4:393; 5:110, 124). But we can represent virtue andhappiness as necessarily combined only by representing virtue as theefficient cause of happiness. This means that we must represent thehighest good not simply as a state of affairs in which everyone is bothhappy and virtuous, but rather as one in which everyone is happy becausethey are virtuous (5:113–114, 124). However, it is beyond the power ofhuman beings, both individually and collectively, to guarantee thathappiness results from virtue, and we do not know any law of nature thatguarantees this either. Therefore, we must conclude that the highest goodis impossible, unless we postulate “the existence of a cause of nature,distinct from nature, which contains the ground of this connection, namely

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distinct from nature, which contains the ground of this connection, namelythe exact correspondence of happiness with morality” (5:125). This causeof nature would have to be God since it must have both understanding andwill. Kant probably does not conceive of God as the efficient cause of ahappiness that is rewarded in a future life to those who are virtuous in thisone. Rather, his view is probably that we represent our endless progresstoward holiness, beginning with this life and extending into infinity, as theefficient cause of our happiness, which likewise begins in this life andextends to a future one, in accordance with teleological laws that Godauthors and causes to harmonize with efficient causes in nature (A809–812/B837–840; 5:127–131, 447–450).

Both of these arguments are subjective in the sense that, rather thanattempting to show how the world must be constituted objectively inorder for the highest good to be possible, they purport to show only howwe must conceive of the highest good in order to be subjectively capableboth of representing it as possible and of fulfilling our duty to promote it.But Kant also claims that both arguments have an objective basis: first, inthe sense that it cannot be proven objectively either that immortality orGod's existence are impossible; and, second, in the sense that botharguments proceed from a duty to promote the highest good that is basednot on the subjective character of human reason but on the moral law,which is objectively valid for all rational beings. So while it is not,strictly speaking, a duty to believe in God or immortality, we mustbelieve both in order to fulfill our duty to promote the highest good, giventhe subjective character of human reason.

To see why, consider what would happen if we did not believe in God orimmortality, according to Kant. In the Critique of Pure Reason, Kantseems to say that this would leave us without any incentive to be moral,and even that the moral law would be invalid without God andimmortality (A813/B841, A468/B496). But Kant later rejects this view(8:139). His mature view is that our reason would be in conflict with itself

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(8:139). His mature view is that our reason would be in conflict with itselfif we did not believe in God and immortality, because pure practicalreason would represent the moral law as authoritative for us and sopresent us with an incentive that is sufficient to determine our will; butpure theoretical (i.e., speculative) reason would undermine this incentiveby declaring morality an empty ideal, since it would not be able toconceive of the highest good as possible (5:121, 143, 471–472, 450–453).In other words, the moral law would remain valid and provide anyrational being with sufficient incentive to act from duty, but we would beincapable of acting as rational beings, since “it is a condition of havingreason at all [...] that its principles and affirmations must not contradictone another” (5:120). The only way to bring speculative and practicalreason “into that relation of equality in which reason in general can beused purposively” is to affirm the postulates on the grounds that purepractical reason has primacy over speculative reason. This means, Kantexplains, that if the capacity of speculative reason “does not extend toestablishing certain propositions affirmatively, although they do notcontradict it, as soon as these same propositions belong inseparably to thepractical interest of pure reason it must accept them [...,] being mindful,however, that these are not its insights but are yet extensions of its usefrom another, namely a practical perspective” (5:121). The primacy ofpractical reason is a key element of Kant's response to the crisis of theEnlightenment, since he holds that reason deserves the sovereignauthority entrusted to it by the Enlightenment only on this basis.

7. The unity of nature and freedom

This final section briefly discusses how Kant attempts to unify thetheoretical and practical parts of his philosophical system in the Critiqueof the Power of Judgment.

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7.1 The great chasm

In the Preface and Introduction to the Critique of the Power of Judgment,Kant announces that his goal in the work is to “bring [his] entire criticalenterprise to an end” by bridging the “gulf” or “chasm” that separates thedomain of his theoretical philosophy (discussed mainly in the Critique ofPure Reason) from the domain of his practical philosophy (discussedmainly in the Critique of Practical Reason) (5:170, 176, 195). In hiswords: “The understanding legislates a priori for nature, as object of thesenses, for a theoretical cognition of it in a possible experience. Reasonlegislates a priori for freedom and its own causality, as the supersensiblein the subject, for an unconditioned practical cognition. The domain of theconcept of nature under the one legislation and that of the concept offreedom under the other are entirely barred from any mutual influencethat they could have on each other by themselves (each in accordancewith its fundamental laws) by the great chasm that separates thesupersensible from the appearances” (5:195).

One way to understand the problem Kant is articulating here is toconsider it once again in terms of the crisis of the Enlightenment.[27] Thecrisis was that modern science threatened to undermine traditional moraland religious beliefs, and Kant's response is to argue that in fact theseessential interests of humanity are consistent with one another whenreason is granted sovereignty and practical reason is given primacy overspeculative reason. But the transcendental idealist framework withinwhich Kant develops this response seems to purchase the consistency ofthese interests at the price of sacrificing a unified view of the world andour place in it. If science applies only to appearances, while moral andreligious beliefs refer to things in themselves or “the supersensible,” thenhow can we integrate these into a single conception of the world thatenables us to transition from the one domain to the other? Kant's solutionis to introduce a third a priori cognitive faculty, which he calls the

Immanuel Kant


is to introduce a third a priori cognitive faculty, which he calls thereflecting power of judgment, that gives us a teleological perspective onthe world. Reflecting judgment provides the concept of teleology orpurposiveness that bridges the chasm between nature and freedom, andthus unifies the theoretical and practical parts of Kant's philosophy into asingle system (5:196–197).

It is important to Kant that a third faculty independent of bothunderstanding and reason provides this mediating perspective, because heholds that we do not have adequate theoretical grounds for attributingobjective teleology to nature itself, and yet regarding nature asteleological solely on moral grounds would only heighten the disconnectbetween our scientific and moral ways of viewing the world. Theoreticalgrounds do not justify us in attributing objective teleology to nature,because it is not a condition of self-consciousness that our understandingconstruct experience in accordance with the concept of teleology, whichis not among Kant's categories or the principles of pure understandingthat ground the fundamental laws of nature. That is why his theoreticalphilosophy licenses us only in attributing mechanical causation to natureitself. In this respect, Kant is sympathetic to the dominant strain inmodern philosophy that banishes final causes from nature and insteadtreats nature as nothing but matter in motion, which can be fully describedmathematically. But Kant wants somehow to reconcile this mechanisticview of nature with a conception of human agency that is essentiallyteleological. For as we saw in the previous section, Kant holds that everyhuman action has an end and that the sum of all moral duties is topromote the highest good. It is essential to Kant's approach, however, tomaintain the autonomy of both understanding (in nature) and reason (inmorality), without allowing either to encroach on the other's domain, andyet to harmonize them in a single system. This harmony can beorchestrated only from an independent standpoint, from which we do notjudge how nature is constituted objectively (that is the job ofunderstanding) or how the world ought to be (the job of reason), but from

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understanding) or how the world ought to be (the job of reason), but fromwhich we merely regulate or reflect on our cognition in a way that enablesus to regard it as systematically unified. According to Kant, this is thetask of reflecting judgment, whose a priori principle is to regard nature aspurposive or teleological, “but only as a regulative principle of the facultyof cognition” (5:197).

7.2 The purposiveness of nature

In the Critique of the Power of Judgment, Kant discusses four main waysin which reflecting judgment leads us to regard nature as purposive: first,it leads us to regard nature as governed by a system of empirical laws;second, it enables us to make aesthetic judgments; third, it leads us tothink of organisms as objectively purposive; and, fourth, it ultimatelyleads us to think about the final end of nature as a whole.[28]

First, reflecting judgment enables us to discover empirical laws of natureby leading us to regard nature as if it were the product of intelligentdesign (5:179–186). We do not need reflecting judgment to grasp the apriori laws of nature based on our categories, such as that every event hasa cause. But in addition to these a priori laws nature is also governed byparticular, empirical laws, such as that fire causes smoke, which wecannot know without consulting experience. To discover these laws, wemust form hypotheses and devise experiments on the assumption thatnature is governed by empirical laws that we can grasp (Bxiii-xiv).Reflecting judgment makes this assumption through its principle to regardnature as purposive for our understanding, which leads us to treat natureas if its empirical laws were designed to be understood by us (5:180–181).Since this principle only regulates our cognition but is not constitutive ofnature itself, this does not amount to assuming that nature really is theproduct of intelligent design, which according to Kant we are not justifiedin believing on theoretical grounds. Rather, it amounts only toapproaching nature in the practice of science as if it were designed to be

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approaching nature in the practice of science as if it were designed to beunderstood by us. We are justified in doing this because it enables us todiscover empirical laws of nature. But it is only a regulative principle ofreflecting judgment, not genuine theoretical knowledge, that nature ispurposive in this way.

Second, Kant thinks that aesthetic judgments about both beauty andsublimity involve a kind of purposiveness, and that the beauty of nature inparticular suggests to us that nature is hospitable to our ends. Accordingto his aesthetic theory, we judge objects to be beautiful not because theygratify our desires, since aesthetic judgments are disinterested, but ratherbecause apprehending their form stimulates what he calls the harmonious“free play” of our understanding and imagination, in which we take adistinctively aesthetic pleasure (5:204–207, 217–218, 287). So beauty isnot a property of objects, but a relation between their form and the wayour cognitive faculties work. Yet we make aesthetic judgments that claimintersubjective validity because we assume that there is a common sensethat enables all human beings to communicate aesthetic feeling (5:237–240, 293–296). Beautiful art is intentionally created to stimulate thisuniversally communicable aesthetic pleasure, although it is effective onlywhen it seems unintentional (5:305–307). Natural beauty, however, isunintentional: landscapes do not know how to stimulate the free play ofour cognitive faculties, and they do not have the goal of giving usaesthetic pleasure. In both cases, then, beautiful objects appear purposiveto us because they give us aesthetic pleasure in the free play of ourfaculties, but they also do not appear purposive because they either do notor do not seem to do this intentionally. Kant calls this relation betweenour cognitive faculties and the formal qualities of objects that we judge tobe beautiful “subjective purposiveness” (5:221). Although it is onlysubjective, the purposiveness exhibited by natural beauty in particularmay be interpreted as a sign that nature is hospitable to our moral interests(5:300). Moreover, Kant also interprets the experience of sublimity innature as involving purposiveness. But in this case it is not so much the

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nature as involving purposiveness. But in this case it is not so much thepurposiveness of nature as our own purpose or “vocation” as moral beingsthat we become aware of in the experience of the sublime, in which thesize and power of nature stand in vivid contrast to the superior power ofour reason (5:257–260, 267–269).

Third, Kant argues that reflecting judgment enables us to regard livingorganisms as objectively purposive, but only as a regulative principle thatcompensates for our inability to understand them mechanistically, whichreflects the limitations of our cognitive faculties rather than any intrinsicteleology in nature. We cannot understand organisms mechanisticallybecause they are “self-organizing” beings, whose parts are “combinedinto a whole by being reciprocally the cause and effect of their form”(5:373–374). The parts of a watch are also possible only through theirrelation to the whole, but that is because the watch is designed andproduced by some rational being. An organism, by contrast, produces andsustains itself, which is inexplicable to us unless we attribute to organismspurposes by analogy with human art (5:374–376). But Kant claims that itis only a regulative principle of reflecting judgment to regard organismsin this way, and that we are not justified in attributing objectivepurposiveness to organisms themselves, since it is only “because of thepeculiar constitution of my cognitive faculties [that] I cannot judge aboutthe possibility of those things and their generation except by thinking of acause for these acts in accordance with intentions” (5:397–398).Specifically, we cannot understand how a whole can be the cause of itsown parts because we depend on sensible intuition for the content of ourthoughts and therefore must think the particular (intuition) first bysubsuming it under the general (a concept). To see that this is just alimitation of the human, discursive intellect, imagine a being with anintuitive understanding whose thought does not depend, as ours does, onreceiving sensory information passively, but rather creates the content ofits thought in the act of thinking it. Such a (divine) being couldunderstand how a whole can be the cause of its parts, since it could grasp

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understand how a whole can be the cause of its parts, since it could graspa whole immediately without first thinking particulars and then combiningthem into a whole (5:401–410). Therefore, since we have a discursiveintellect and cannot know how things would appear to a being with anintuitive intellect, and yet we can only think of organisms teleologically,which excludes mechanism, Kant now says that we must think of bothmechanism and teleology only as regulative principles that we need toexplain nature, rather than as constitutive principles that describe hownature is intrinsically constituted (5:410ff.).

Fourth, Kant concludes the Critique of the Power of Judgment with a longappendix arguing that reflecting judgment supports morality by leading usto think about the final end of nature, which we can only understand inmoral terms, and that conversely morality reinforces a teleologicalconception of nature. Once it is granted on theoretical grounds that wemust understand certain parts of nature (organisms) teleologically,although only as a regulative principle of reflecting judgment, Kant sayswe may go further and regard the whole of nature as a teleological system(5:380–381). But we can regard the whole of nature as a teleologicalsystem only by employing the idea of God, again only regulatively, as itsintelligent designer. This would be to attribute what Kant calls externalpurposiveness to nature — that is, to attribute purposes to God in creatingnature (5:425). What, then, is God's final end in creating nature?According to Kant, the final end of nature must be human beings, butonly as moral beings (5:435, 444–445). This is because only humanbeings use reason to set and pursue ends, using the rest of nature asmeans to their ends (5:426–427). Moreover, Kant claims that humanhappiness cannot be the final end of nature, because as we have seen heholds that happiness is not unconditionally valuable (5:430–431). Rather,human life has value not because of what we passively enjoy, but onlybecause of what we actively do (5:434). We can be fully active andautonomous, however, only by acting morally, which implies that Godcreated the world so that human beings could exercise moral autonomy.

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created the world so that human beings could exercise moral autonomy.Since we also need happiness, this too may be admitted as a conditionedand consequent end, so that reflecting judgment eventually leads us to thehighest good (5:436). But reflection on conditions of the possibility of thehighest good leads again to Kant's moral argument for belief in God'sexistence (he now omits immortality), which in turn reinforces theteleological perspective on nature with which reflecting judgment began.

Thus Kant argues that although theoretical and practical philosophyproceed from separate and irreducible starting points — self-consciousness as the highest principle for our cognition of nature, and themoral law as the basis for our knowledge of freedom — reflectingjudgment unifies them into a single, teleological worldview that assignspreeminent value to human autonomy.

Bibliography

Primary Literature

Works by Kant

The standard German edition of Kant's works is: KöniglichenPreußischen (later Deutschen) Akademie der Wissenschaften (ed.),1900-, Kants gesammelte Schriften, Berlin: Georg Reimer (laterWalter De Gruyter).The best English edition of Kant's works is: P. Guyer and A. Wood(eds.), 1992-, The Cambridge Edition of the Works of ImmanuelKant, Cambridge: Cambridge University Press. Its individualvolumes are:

Allison, H., and Heath, P., (eds.), 2002, Theoretical Philosophyafter 1781, Cambridge: Cambridge University Press.Ameriks, K., and Naragon, S., (eds.), 1997, Lectures onMetaphysics, Cambridge: Cambridge University Press.

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Metaphysics, Cambridge: Cambridge University Press.Förster, E., (ed.), 1993, Opus Postumum, Cambridge:Cambridge University Press.Gregor, M., (ed.), 1996, Practical Philosophy, Cambridge:Cambridge University Press.Guyer, P., and Wood, A., (eds.), 1998, Critique of Pure Reason,Cambridge: Cambridge University Press.Guyer, P., (ed.), 2000, Critique of the Power of Judgment,Cambridge: Cambridge University Press.Guyer, P., (ed.), 2005, Notes and Fragments, Cambridge:Cambridge University Press.Heath, P., and Schneewind, J., (eds.), 1997, Lectures on Ethics,Cambridge: Cambridge University Press.Walford, D., and Meerbote, R., (eds.), 1992, TheoreticalPhilosophy, 1755–1770, Cambridge: Cambridge UniversityPress.Wood, A., and di Giovanni, G., (eds.), 1996, Religion andRational Theology, Cambridge: Cambridge University Press.Young, J., (ed.), 1992, Lectures on Logic, Cambridge:Cambridge University Press.Zöller, G., and Louden, R., (eds.), 2007, Anthropology, History,and Education, Cambridge: Cambridge University Press.Zweig, A., (ed.), 1999, Correspondence, Cambridge:Cambridge University Press.

Other Primary Sources

Jacobi, F., 1787, David Hume on Faith or Idealism and Realism: ADialogue, in G. di Giovanni (ed.), The Main Philosophical Writingsand the Novel Allwill, Montreal: McGill-Queen's University Press,1994.

Fichte, J., 1792, Attempt at a Critique of All Revelation, in G. Green(ed.), Attempt at a Critique of All Revelation, Cambridge: Cambridge

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(ed.), Attempt at a Critique of All Revelation, Cambridge: CambridgeUniversity Press, 1978.

Locke, J. 1689, An Essay Concerning Human Understanding, in P.Nidditch (ed.), An Essay Concerning Human Understanding, Oxford:Clarendon Press, 1975.

Reinhold, K., 1786–1790, Letters on the Kantian Philosophy, in K.Ameriks (ed.), Letters on the Kantian Philosophy, Cambridge:Cambridge University Press, 2005.

Sassen, B., 2000, Kant's Early Critics: The Empiricist Critique of theTheoretical Philosophy, Cambridge: Cambridge University Press.

Secondary Literature

Allison, H., 1990, Kant's Theory of Freedom, Cambridge: CambridgeUniversity Press.

–––, 2001, Kant's Theory of Taste: A Reading of the Critique of AestheticJudgment, Cambridge: Cambridge University Press.

–––, 2004, Kant's Transcendental Idealism: An Interpretation andDefense, New Haven and London: Yale University Press, Revisedand Enlarged Edition.

–––, 1996, Idealism and Freedom: Essays on Kant's Theoretical andPractical Philosophy, Cambridge: Cambridge University Press.

Ameriks, K., 1978, “Kant's Transcendental Deduction as a RegressiveArgument,” Kant-Studien, 69: 273-87; reprinted in Kitcher (ed.)1998, pp. 85–102; and in Ameriks 2003, pp. 51–66.

–––, 1982, “Recent Work on Kant's Theoretical Philosophy,” AmericanPhilosophical Quarterly, 19: 1–24; reprinted in Ameriks 2003, pp.67–97.

–––, 1992, “Kantian Idealism Today,” History of Philosophy Quarterly, 9:329–342; reprinted in Ameriks 2003, 98–111.

–––, 2003, Intepreting Kant's Critiques, Oxford: Clarendon Press.Aquila, R., 1983, Representational Mind: A Study of Kant's Theory of

Knowledge, Bloomington: Indiana University Press.

Immanuel Kant


Knowledge, Bloomington: Indiana University Press.Beck, L., 1960, A Commentary on Kant's Critique of Practical Reason,

Chicago and London: University of Chicago Press.–––, 1965, “The fact of reason: an essay on justification in ethics,” in

Beck (ed.), Studies in the Philosophy of Kant, Indianapolis: Bobbs-Merrill, pp. 200-214; reprinted in Beck 2002, pp. 45-56.

–––, 1978, “Did the Sage of Königsberg Have No Dreams?” in Beck,Essays on Kant and Hume, New Haven:Yale University Press;reprinted in Beck 2002, pp. 85–101; and in Kitcher (ed.) 1998, pp.103–116.

–––, 2002, Selected Essays on Kant (Series: North American Kant SocietyStudies in Philosophy), H. Robinson (ed.), Rochester: University ofRochester Press.

Beiser, F., 1987, The Fate of Reason: German Philosophy from Kant toFichte, Cambridge and London: Harvard University Press.

–––, 2000, “The Enlightenment and Idealism,” in The CambridgeCompanion to German Idealism, K. Ameriks (ed.), Cambridge:Cambridge University Press, pp. 18–36.

–––, 2002, German Idealism: The Struggle Against Subjectivism, 1781–1801, Cambridge and London: Harvard University Press.

Bennett, J., 1966, Kant's Analytic, Cambridge: Cambridge UniversityPress.

–––, 1974, Kant's Dialectic, Cambridge: Cambridge University Press.Bird, G., 1962, Kant's Theory of Knowledge: An Outline of One Central

Argument in the Critique of Pure Reason, London: Routledge &Kegan Paul.

–––, 2006, The Revolutionary Kant: A Commentary on the Critique ofPure Reason, Chicago and La Salle: Open Court.

Engstrom, S. 1992, “The Concept of the Highest Good in Kant's MoralTheory,” Philosophy and Phenomenological Research, 52(4): 747–780.

Michael Rohlf


Förster, E., 1989, (ed.), Kant's Transcendental Deductions, Stanford:Stanford University Press.

Gardner, S., 1999, Kant and the Critique of Pure Reason, London andNew York: Routledge.

Grier, M. 2001, Kant's Doctrine of Transcendental Illusion, Cambridge:Cambridge University Press.

Ginsborg, H., 1997, “Kant on Aesthetic and Biological Purposiveness,” inB. Herman, C. Korsgaard, and T. Hill (eds.), Reclaiming the Historyof Ethics: Essays in Honor of John Rawls, Cambridge: HarvardUniversity Press, pp. 329–360.

–––, 2001, “Kant on Understanding Organisms as Natural Purposes,” inE. Watkins (ed.), Kant and the Sciences, Oxford: Oxford UniversityPress.

–––, 2006, “Thinking the Particular as Contained in the Universal,” inKukla (ed.) 2006, pp. 35–60.

Guyer, P., 1987, Kant and the Claims of Knowledge, Cambridge:Cambridge University Press.

–––, 1992, “The transcendental deduction of the categories,” in Guyer(ed.) 1992, pp. 123–160.

–––, 1993, Kant and the Experience of Freedom, Cambridge: CambridgeUniversity Press.

–––, 1997, Kant and the Claims of Taste, Cambridge: CambridgeUniversity Press, 2nd edition.

–––, 2000, Kant on Freedom, Law, and Happiness, Cambridge:Cambridge University Press.

–––, 2005, Kant's System of Nature and Freedom, Oxford: ClarendonPress.

–––, 2006, Kant, London and New York: Routledge.–––, (ed.), 1992, The Cambridge Companion to Kant, Cambridge:

Cambridge University Press.–––, (ed.), 2006, The Cambridge Companion to Kant and Modern

Philosophy, Cambridge: Cambridge University Press.

Immanuel Kant


Philosophy, Cambridge: Cambridge University Press.–––, (ed.), 2010, The Cambridge Companion to Kant's Critique of Pure

Reason, Cambridge: Cambridge University Press.Henrich, D., 1969, “The Proof-Structure of Kant's Transcendental

Deduction,” Review of Metaphysics, 22: 640–59.–––, 1976, Identität und Objektivität: Eine Untersuchung über Kants

transzendentale Deduktion, Heidelberg: Carl WinterUniversitätsverlag.

–––, 1992, Aesthetic Judgment and the Moral Image of the World: Studiesin Kant, Stanford: Stanford University Press.

–––, 1994, The Unity of Reason: Essays on Kant's Philosophy, R. Velkley(ed.), Cambridge and London: Harvard University Press.

Hill, T., 1992, Dignity and Practical Reason in Kant's Moral Theory,Ithaca: Cornell University Press.

Kemp Smith, N., 1923, Commentary to Kant's Critique of Pure Reason,New York: Humanities Press, 2nd edition (1992 reprint).

Kitcher, P., (ed.), 1998, Kant's Critique of Pure Reason: Critical Essays,Lanham, Maryland: Rowman & Littlefield.

Kleingeld, P., 1995, “What do the Virtuous Hope for? Re-reading Kant'sDoctrine of the Highest Good,” in H. Robinson (ed.), Proceedings ofthe Eight International Kant Congress, Milwaukee: MarquetteUniversity Press, 1:91–112.

Korsgaard, C., 1996, Creating The Kingdom of Ends, Cambridge:Cambridge University Press.

Kuehn, M., 2001, Kant: A Biography, Cambridge: Cambridge UniversityPress.

Kukla, R., (ed.), 2006, Aesthetics and Cognition in Kant's CriticalPhilosophy, Cambridge: Cambridge University Press.

Langton, R., 1998, Kantian Humility: Our Ignorance of Things inThemselves, Oxford: Clarendon Press.

Longuenesse, B., 1998. Kant and the Capacity to Judge: Sensibility andDiscursivity in the Transcendental Analytic of the Critique of Pure

Michael Rohlf


Discursivity in the Transcendental Analytic of the Critique of PureReason, Princeton: Princeton University Press.

–––, 2005, Kant on the Human Standpoint, Cambridge: CambridgeUniversity Press.

–––, 2006, “Kant on a priori concepts: The metaphysical deduction of thecategories,” in Guyer (ed.) 2006, pp. 129–168; also in Longuenesse2005, pp. 81–116.

McFarland, J., 1970, Kant's Concept of Teleology, Edinburgh: universityof Edinburgh Press.

Neiman, S., 1994, The Unity of Reason: Rereading Kant, Oxford: OxfordUniversity Press.

O'Neill, Onora, 1989, Constructions of Reason, Cambridge: CambridgeUniversity Press.

Paton, H., 1936, Kant's Metaphysic of Experience, London: Allen &Unwin.

–––, 1947, The Categorical Imperative, Philadelphia: University ofPennsylvania Press (1971 reprint).

Prauss, G., 1974, Kant und das Problem der Dinge an sich, Bonn:Bouvier.

Rawls, J., 2000, Lectures on the History of Moral Philosophy, B. Herman(ed.), Cambridge and New York: Harvard University Press.

Reath, A., 1988, “Two Conceptions of the Highest Good in Kant,”Journal of the History of Philosophy, 26: 593–619.

Robinson, H., 1994, “Two Perspectives on Kant's Appearances andThings in Themselves,” Journal of the History of Philosophy, 32:411–441.

Rohlf, M., 2008, “The Transition From Nature to Freedom in Kant'sThird Critique,” Kant-Studien, 99 (3): 339-360.

–––, 2010, “The Ideas of Pure Reason,” in Guyer (ed.) 2010.Silber, J., 1959, “Kant's Conception of the Highest Good as Immanent

and Transcendent,” The Philosophical Review, 68: 469–492.

Immanuel Kant


Strawson, P., 1966, The Bounds of Sense: An Essay on Kant's Critique ofPure Reason, London and New York: Routledge.

Sullivan, R., 1989, Immanuel Kant's Moral Theory, Cambridge:Cambridge University Press.

–––, 1994, An Introduction to Kant's Ethics, Cambridge: CambridgeUniversity Press.

Van Cleve, J., 1999, Problems From Kant, New York and Oxford:Oxford University Press.

Walford, D. and Meerbote, R., 1992, “General Introduction” and“Introductions to the translations,” in Immanuel Kant: TheoreticalPhilosophy, 1755–1770, Cambridge: Cambridge University Press,pp. xxxv-lxxiv.

Wood, A., 1970, Kant's Moral Religion, Ithaca: Cornell University Press.–––, 1984, “Kant's Compatibilism,” in Wood (ed.), Self and Nature in

Kant's Philosophy, Ithaca and London: Cornell University Press, pp.73–101; reprinted in Kitcher (ed.) 1998, pp. 239–263.

–––, 1999, Kant's Ethical Thought, Cambridge: Cambridge UniversityPress.

–––, 2005, Kant, Oxford: Blackwell.Zuckert, R., 2007, Kant on Beauty and Biology: An Interpretation of the

Critique of Judgment, Cambridge: Cambridge University Press.

Other Internet Resources

Kant on the WebEpistemeLinksKant-Forschungsstelle (Mainz)North American Kant Society

Related Entries

aesthetics: German, in the 18th century | categories | Fichte, JohannGottlieb | Kant, Immanuel: account of reason | Kant, Immanuel: aesthetics

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Gottlieb | Kant, Immanuel: account of reason | Kant, Immanuel: aestheticsand teleology | Kant, Immanuel: and Hume on causality | Kant,Immanuel: and Hume on morality | Kant, Immanuel: and Leibniz | Kant,Immanuel: critique of metaphysics | Kant, Immanuel: moral philosophy |Kant, Immanuel: philosophical development | Kant, Immanuel:philosophy of mathematics | Kant, Immanuel: philosophy of religion |Kant, Immanuel: philosophy of science | Kant, Immanuel: social andpolitical philosophy | Kant, Immanuel: theory of judgment | Kant,Immanuel: transcendental arguments | Kant, Immanuel: view of mind andconsciousness of self | Kant, Immanuel: views on space and time |Leibniz, Gottfried Wilhelm | metaphysics | Reinhold, Karl Leonhard |Wolff, Christian

Notes to Immanuel Kant

1. The best biography of Kant, on which this section draws, is Kuehn2001.

2. Kuehn 2001, 38, 44. See also 54.

3. See Walford and Meerbote 1992; and Kant, Immanuel: philosophicaldevelopment.

4. Citations from Kant's texts refer to volume and page numbers in theAkademie edition (see bibliography), except for references to the Critiqueof Pure Reason, which is cited by page numbers in the original first (A)and second (B) editions. All quotations from Kant follow, with someminor alterations, the English translations in The Cambridge Edition ofthe Works of Immanuel Kant (see bibliography).

5. See Gardner 1999, chapters 1-2; and Beiser 2000.

6. Bird 2006, 31.

Immanuel Kant


7. In the Prolegomena, Kant renames it “critical idealism,” but this namedid not stick (4:293).

8. See also A369, which however occurs only in the first edition. Forfurther discussion, see Kant, Immanuel: views on space and time.

9. Garve's original review was drastically shortened, heavily edited, andpublished anonymously by Feder in January, 1782. Kant replied directlyin the Prolegomena (4:372ff.). Both Garve's original review and theversion edited by Feder are translated and discussed in Sassen 2000.

10. Recent proponents of the two-objects interpretation include Strawson1966, Aquila 1983, Guyer 1987, and Van Cleve 1999.

11. Recent proponents of the two-aspects interpretation include Bird 1962,Bird 2006, Prauss 1974, Langton 1998, and Allison 2004.

12. For example, Bxviii-xix, A38-39/B55-56, A42/B59, A247/B303,A490-491/B518-519, and passages about the problematic boundaryconcept of noumena in the chapter on Phenomena and Noumena and atthe end of the Amphiboly.

13. For examples and discussion, see Robinson 1994 and Ameriks 1992.See also Allison's replies in Allison 1996, chapter 1.

14. For example, see Henrich 1969; Henrich 1976; Ameriks 1978; Guyer1987, part II; Guyer 1992; Longuenesse 1998; Longuenesse 2005, part I;Allison 2004, chapter 7; and Bird 2006, chapters 13-16. See also Kant,Immanuel: theory of judgment, Kant, Immanuel: transcendentalarguments, and Kant, Immanuel: view of mind and consciousness of self.

15. See also A116 and Guyer 1987, 132-139.

16. In fact, these too are judgments, which in the Prolegomena Kant callsjudgments of perception (4:298-299). But they are judgments about my

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judgments of perception (4:298-299). But they are judgments about mysubjective states rather than about objects distinct from me. As judgmentsthey have a truth value: it is either true or false that I feel nostalgia when Isee this house. Kant's point, however, is that I can make such judgmentsabout my own subject only if I also make judgments about objectsdistinct from me. Merely subjective judgments of perception are parasiticon objectively valid judgments of experience, because self-consciousnessrequires that I place myself in an objective world and refer at least someof my representations to objects distinct from me. See Beck 1978.

17. See A66-83/B91-116, B159, and Longuenesse (2006).

18. Kant calls space, in particular, an “ens imaginarium” or being of theimagination to emphasize that on his view we are not somehow consciousof the whole of space, which he also describes as “an infinite givenmagnitude” (292/B348-349, A25/B39). Rather, we are conscious of spaceonly to the extent that we represent objects in it, but we must representobjects in a single space and cannot represent any boundaries of space.See Longuenesse 2005, chapter 3.

19. See Kemp Smith 1923, 2; and Kant, Immanuel: account of reason.

20. See Rohlf 2010, Grier 2001, and Kant, Immanuel: critique ofmetaphysics.

21. See Wood 1984 and Allison 1990. Kant's important discussions offreedom include not only the texts cited here from the Critique ofPractical Reason, but also the third antinomy and its resolution in theCritique of Pure Reason and section III of the Groundwork.

22. For further discussion of Kant's practical philosophy, see Kant,Immanuel: moral philosophy, Kant, Immanuel: and Hume on morality,and Kant, Immanuel: social and political philosophy.

Immanuel Kant


23. See Rohlf 2010.

24. See Beck 1960, 244-45; and Wood 1970, 95-96.

25. See Silber 1959; Wood 1970, 94-95; Reath 1988; and Engstrom 1992,776-777.

26. See Wood 1970, chapter 4; Guyer 2000, chapter 10; and Kant,Immanuel: philosophy of religion.

27. Rohlf 2008 develops another way of understanding this problem thatemphasizes its moral significance for Kant.

28. See Guyer 1997; Allison 2001; Zuckert 2007; and Kant, Immanuel:aesthetics and teleology.

Copyright © 2010 by the author Michael Rohlf

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